Trump and Pence bombard Senate Democrats in the Midwest as control of the chamber hangs in the balance

• President Donald Trump and Vice President Mike Pence head to Indiana and Wisconsin, respectively, to campaign in key Senate races.
• Trump will try to hit Democratic Sen. Joe Donnelly and boost his Republican opponent Mike Braun, while Pence will support Republican Leah Vukmir in her bid to beat Democratic Sen. Tammy Baldwin.
• Pence also went to Michigan this week to boost Republican John James in his race against Democratic Sen. Debbie Stabenow.
• Running in a state Trump won by about 20 percentage points, Donnelly has tied himself much more closely to the president than Baldwin or Stabenow have.

Nicholas Kamm | AFP | Getty Images

President Donald Trump and Vice President Mike Pence 

The White House takes its onslaught on vulnerable Senate Democrats to two Midwestern states Thursday night as Republicans try to expand their majority in the chamber.

President Donald Trump will hold a rally in Indiana, where incumbent Democratic Sen. Joe Donnelly faces a challenge from GOP businessman Mike Braun in a state the president carried by about 20 percentage points in 2016. Vice President Mike Pence will campaign in Wisconsin for Republican state Sen. Leah Vukmir, who aims to take out Democratic Sen. Tammy Baldwin in a state the president won by a razor-thin margin.

Pence's trip to the Badger State follows a Wednesday fundraising stop in Michigan for Republican veteran and businessman John James. He is challenging Sen. Debbie Stabenow, a Democratic incumbent who faces re-election in another state that Trump only narrowly won.

The White House's Midwestern blitz underscores the wealth of opportunities the GOP has to try to flip Democratic Senate seats this year. Democrats and independents who caucus with them have to defend 26 seats, including 10 in states the president won in 2016, giving them a slim chance of taking control of the Senate. Trump has repeatedly complained that Republicans' current 51-49 seat majority in the Senate is too narrow for him to accomplish his policy goals, such as repealing the Affordable Care Act.

Trump's and Pence's visits also highlight the varying strategies Democratic Senate incumbents have had to adopt as they fight for their political survival in distinct states. While most Senate Democrats defending their seats in Trump states have prioritized health-care policy, some in the darker red states have also tried to tie themselves to Trump both through their words and votes.

Take Donnelly, who is considered one of the most endangered senators in his party this year. He has voted with Trump's priorities more than half the time, and repeatedly emphasized his efforts to work with Republicans. A Donnelly campaign ad released this week highlights the senator's vote for Trump's immigration package this year "to build a wall and protect our borders," over video of him shaking the president's hand.

Trump has hardly returned the flattery. When he visited Indiana in May, he dubbed Donnelly "Sleepin' Joe" and contended that he is too liberal for Indiana. Though Donnelly has supported Trump on immigration, judicial nominations and other issues, the president has focused his ire on unified Democratic opposition to both last year's failed efforts to repeal the Affordable Care Act and the GOP's tax overhaul that passed in December.

While independent polling has been limited so far, most signs point to a close race in Indiana.

Michael Brochstein | SOPA Images | LightRocket | Getty Images

Sen. Debbie Stabenow (D-MI) at a press conference at the US Capitol.

Running in states Trump won not far from the Hoosier State, Baldwin and Stabenow have kept their distance from the president. Trump's 2016 margin of victory of less than a percentage point in both Wisconsin and Michigan at least partly explains the difference in strategy.

"Michigan needs a Senator who puts Michigan first, not Donald Trump and Mike Pence," Stabenow's campaign tweeted ahead of Pence's visit to the state Wednesday.

Stabenow tweet

Baldwin has only voted with the president's priorities about 23 percent of the time. Stabenow has sided with Trump more often, but still aligned with him on only about 32 percent of her votes.

In one sign of their lack of deference to Trump, both Baldwin and Stabenow have already said they will oppose the president's Supreme Court nominee Brett Kavanaugh, who will go before the Senate Judiciary Committee for hearings next week. Trump and Republican groups have tried to pressure Democratic senators facing re-election this year to back the judge — or hammer them for their votes if they do not.

In her statement announcing opposition last month, Baldwin said that Americans "do not want the Supreme Court to advance a political agenda to overturn the law of the land on health care for people with pre-existing conditions, women's reproductive health, and the constitutional rights and freedoms of all Americans." Explaining her decision last month, Stabenow said, "It is clear that [Kavanaugh] has chosen to side with the wealthiest special interests over the majority of Americans time after time."

Both senators appear to have an advantage in their races with more than two months to go. Baldwin leads Vukmir by about 10 percentage points in an average of recent polls, according to RealClearPolitics. Stabenow's edge over James is about 17 percentage points in an average of surveys.

While Donnelly's messaging has differed vastly from both Baldwin's and Stabenow's, all three campaigns have drilled into at least one major issue. The senators have promoted their efforts to preserve Obamacare's protections for pre-existing conditions as the Trump administration backs a pending lawsuit arguing those protections should be considered unconstitutional.

In the same ad this week in which it highlighted Donnelly's cooperation with Trump, the senator's campaign said he is "protecting health care for Hoosiers with pre-existing conditions."

A day before Pence's trip to Wisconsin, Baldwin introduced legislation that aims to stop the Trump administration's expansion of short-term insurance plans, which do not have to comply with the Obamacare rules on pre-existing conditions. Both Donnelly and Stabenow co-sponsored the measure.

While the effort has little chance of getting through Congress, it is part of Democrats' push to keep health care at the top of voters' minds as the White House tries to chip away at Obamacare. Health care consistently ranks as among the most important for voters, and opinion polls have shown Americans generally trust Democrats more than Republicans to handle the issue.