At this point, we know a lot about how Donald J. Trump campaigns. But we know much less about how he would govern.
Trump has shifted positions on a wide range of issues before, after, and during his campaign, making it difficult to know for certain where he would land if he captured the White House. His circle of advisers is also smaller and less cohesive than past Republican candidates: Numerous policy aides from prior GOP administrations have opposed his candidacy, along with every living Republican president and nominee, with the exception of Bob Dole. That makes it difficult to predict who he would appoint to carry out his plans.
There are some hints from his inner circle at top positions, though: According to senior campaign aides, his transition team is eyeing Rudy Giuliani as a possible attorney general and Newt Gingrich as secretary of state. RNC chairman Reince Priebus is also under consideration as Trump's chief of staff.
Should Trump follow through on his more sweeping campaign pledges, policy experts and political veterans see the potential for an explosive four years in office.
In a speech this month, Donald Trump outlined a plan for his first 100 days in office that included a range of policy issues and some more personal items. He renewed his pledge to build a border wall, to undo President Obama's executive orders on immigration and other policies, and potentially to withdraw from NAFTA. On foreign policy, he has advocated an "America First" approach that has alarmed overseas leaders by calling into question alliances like NATO unless countries pay more for protection.
While Hillary Clinton's agenda is likely to be stymied by divided government if she's elected, a Trump victory would mean he'd probably take office with a Republican House and Senate, improving his chances of enacting major legislation. In practice, though, it may be difficult to keep his party together after a divisive race in which many lawmakers called on him to drop out in October (some later re-endorsed him).
At the same time, his platform is less reliant on Congress than Clinton's would be: Many of his biggest promises on trade, immigration, national security, and foreign policy can be achieved through executive action.
"He's going to try to start with a bang by taking as much of Obama off the books with a stroke of his pen as he possibly can," Brookings Senior Fellow William Galston said. "Then it gets tougher."
Compared to Clinton, there's tremendous uncertainty about how he would approach the presidency. Would he follow his running mate Mike Pence's lead, govern within the GOP mainstream, and delegate tasks to more experienced political hands? Or would he feud with Republican leaders and go his own way? When he faces inevitable setbacks will he negotiate compromises, as he has often indicated? Or will he reflexively seek revenge against his perceived enemies, as he has done constantly throughout his campaign?
Trump's first moves could include some personal score-settling. He has said he will appoint a special prosecutor to investigate Hillary Clinton, who he has threatened to jail in campaign speeches and debates, for her use of a private email server as secretary of state and possibly issues connected to her family foundation. He's also warned he may sue women who accused him of sexual misconduct, along with media outlets who covered their allegations. Historically, however, Trump has had a tendency to make legal threats and not follow through.
Trump would also have to figure out what to do with his business empire, which experts warn could present unprecedented conflicts of interest.Trump has not released his taxes and there's much that remains unknown about his debts and business dealings, which could create ethics issues early on. Adding to the mess, Trump has said he'd put his children in charge, a far cry from the type of blind trust that past politicians have used to keep themselves independent from decisions about their finances while they govern.
When it comes to policy, though, his first order of business will likely entail reversing many of President Obama's executive orders immediately upon taking office.
This would likely begin with immigration, where Trump would end Obama's Deferred Action for Childhood Arrivals program that has granted temporary work permits to many "dreamers" -- eligible young immigrants who lacked legal status. He could also ditch Obama's instructions to immigration authorities that they strictly focus on removing criminals instead of targeting otherwise law-abiding undocumented immigrants, a move that could dramatically increase deportations.
Trump could also suspend immigration by refugees from Syria and impose whichever "extreme vetting" requirements he settles on for immigrants from other countries -- the current iteration of what was originally his proposed Muslim ban.
Things get trickier from there, though. His border wall would be "the most difficult to accomplish" on his immigration wish list, former Immigration and Naturalization Service commissioner Doris Meissner said. He would need Congress to approve funding for it in the budget and would face legal obstacles in order to build on vast stretches that pass through private, state, and tribal lands.
Democrats in Congress would oppose construction of the wall out of hand, especially if it's not attached to immigration reform measures including a path to citizenship for existing undocumented immigrants. Republicans would be divided as well, making passage unlikely. Mexico's leadership has also made clear they won't pay for the wall as Trump as promised, and his promise to compel them to do so by cutting off transfer payments by private citizens between Mexico and America may not be legally or politically possible.
Finally, Trump would face the task of nominating a new Supreme Court justice to replace Antonin Scalia, who died last year. He already has put out a growing listof possible names, all of whom are broadly in line with conservative wish lists.
Trump would almost certainly face a global crisis even before he took office, as allies abroad are alarmed by his "America First" rhetoric and stated disregard for the international institutions the United States has led since World War II.
In particular, Trump's threats to abandon NATO countries and military allies like South Korea and Japan if they fail to shoulder more of the cost of American protection have caused a firestorm. He would also have to chart a course with allies in the Muslim world like Saudi Arabia, who he has criticized regularly, after promising to ban all Muslims from America.
"He's taken a stand that is farther than what anyone in the security community has previously advocated," Jacob Shapiro, a professor of international affairs at Princeton, said.
Dozens of foreign leaders, breaking from more typical diplomatic tones towards potential US presidents, have publicly warned Trump would damage relations with their countries and have criticized him in unusually personal terms. A poll by Pew of residents in a variety of European and Asian allies in June found broad opposition to Trump, with majorities and pluralities across the board saying they had "no confidence" in his ability to lead.
Presidents have extremely broad authority on foreign policy and Trump has some big ideas, making this the area early in his presidency to watch most. Does he reach out to reassure foreign leaders that some of his campaign lines were for show? Or does he actively start calling into question international agreements, from military alliances to trade deals to the Geneva Convention, which he has said should be altered to allow torture and other war crimes?
"Many of these questions would be shaped by the foreign policy team around him, about which we know nothing," Galston said. "Virtually the entire Republican foreign policy establishment has jumped ship."
In another flashpoint, Trump has called climate science a hoax and said he'd pull out of the Paris climate agreement, a massive global priority already backed by over 190 countries. He'd also look to undo energy regulations that would keep the US on track to meet the deal's emissions targets that scientists warn are the bare minimum to avoid potentially catastrophic climate change. Among other problems, this would also create instant tension with China which agreed to a major deal with the U.S. on climate emissions ahead of Paris.
When it comes to the war against ISIS, Trump would face immediate questions about how to handle Syria, where he would have an opportunity to put his call for warmer relations with Russia to the test.
It would also be a battleground within the party and likely his own administration. Trump has said repeatedly he'll look for cooperation with Russia, including on a joint military campaign against ISIS, and not pursue avenues to remove Syrian dictator Bashar al-Assad. His running mate Pence, however, said in a nationally televised debate with Tim Kaine that he would threaten Assad with military force over his use of indiscriminate bombing and opposes Russian involvement. Trump later said Pence was wrong.
Pence has also threatened consequences against Russia if they're found to be involved in election related hacks, which Trump has denied is the case despite a consensus assessment by U.S. intelligence officials.
Then there's Trump's top agenda item: Trade.
Trump would likely follow through on his campaign promise to reopen talks on NAFTA with Mexico and Canada, which he has threatened to leave if they go poorly. He's also floated withdrawing from the World Trade Organization, which could set off an international trade war and financial panic, although he has put less emphasis on the idea.
"From what I've noticed, he's moved away from saying he will automatically take the US out of these agreements to saying that he will demand renegotiation," Robert Howse, a professor of international law at New York University, said.
Based on his speeches, Trump could instruct his Treasury Department to label China a "currency manipulator," which may not have much effect in practice. He also could use his authority to slap tariffs on imported goods he believes are illegally subsidized or dumped into the United States from other countries, something that both the current and former administrations have done. Companies could appeal if they believe they've been illegally singled out, though, and more blanket nationwide tariffs -- Trump has mentioned major taxes on Chinese goods -- would require Congressional approval.
Once again, though, there's the question of how many of Trump's promises have been made for show. He's been relatively vague on what demands he would make in trade talks, mostly emphasizing his dealmaking ability and plans to hire better negotiators rather than naming specific items he'd address.
While immigration, trade, and foreign policy might define his early agenda, much of Trump's presidency could be defined by his relationship with Congress.
Once again, the biggest question is whether he delegates policymaking to more traditional Republicans or pursues less conventional ideas that might even cross party lines.
The most likely area of cooperation with Republican leaders is tax reform. Trump has called for a multi-trillion dollar tax cut centered on high earners that's not incompatible with similar proposals from the House GOP. Unlike other legislative items, Senate Republicans could bypass a likely Democratic filibuster and pass it through reconciliation, a process that requires a simple majority.
Speaker Paul Ryan, should he retain his job, has proposed a variety of budget ideas that could be achieved through the same process. It's not clear how many pieces Trump would back, however. He's been especially critical of efforts to overhaul entitlements like Medicare and Social Security while Ryan has made reining in long-term spending on the programs a central priority.
"I assume any efforts to reform entitlements will go by the wayside" if Trump is president, John Feehery, a Republican strategist and former House GOP aide, said.
In general, Trump would likely come into conflict with budget hawks over spending. He's promised a major infrastructure package to go along with his proposed tax cut, a planned increase in defense spending, and more immigration enforcement.
"We don't have as many specifics about his plans as Clinton, but we do know most of what he would do would increase the deficit very substantially," Stan Collender, a former Democratic budget aide, said.
Trump would face enormous pressure to address is Obamacare, which he and most other Republicans have promised to repeal and replace should they gain control of government.
The question, however, is what to replace it with. Trump has hewed to the traditional Republican line about allowing insurers to cross state lines and expand health savings costs, but he's also said he would protect people with preexisting conditions, as Obamacare does. Trump has proposed allowing Medicare to negotiate lower prices with drug companies, an item that has generally garnered Democratic support and Republican opposition.
Once again, Trump's constant flip flops make it hard to discern where he would go. He said earlier in the race he would seek universal health care and even praised Obamacare's mandate to buy insurance before walking his position back. But without major changes, his current proposals would kick tens of millions of people off insurance gained through Obamacare and remove popular consumer protections. This could be a recurring tension in policy fights, where Republicans have demanded major cuts to social programs while Trump's instinct are often to promise the moon.
"I think the question is does he work with Paul Ryan or try to work against him," Feheery said. "Ryan has laid out his blueprint and it's not clear to me how much that will hew to his line."