Indeed, getting a 2018 defense spending bill that both congressional chambers can agree on remains a challenge because there's disagreement over how to pay for it. There's also the hurdle of the current statutory budget caps set by the 2011 Budget Control Act.
The House passed a fiscal 2018 defense spending bill last month that includes a defense topline of $696.5 billion, above the Trump administration's $667 billion plan and also about $70 billion higher than the spending caps mandated by Congress.
But the Senate has yet to vote on a national defense bill, although the Armed Services Committee's version includes a defense topline number of $700 billion, including $60 billion in war-related overseas contingency operations funding.
"In order for the plan to go through, you'd have to change the law [with the Budget Control Act] or everything would be moot," said Frederico Bartels, policy analyst for defense budgeting at the Heritage Foundation, a conservative think tank.
According to Bartels, the likely scenario is Congress will rely again on a short-term spending bill, or a continuing resolution — known as a CR — to keep the government operating and to fund defense operations. He said it likely would be a three-month CR or six-month CR since the government's new fiscal year starts October 1.
In June, Marine Corps Gen. Joseph Dunford, chairman of the Joint Chiefs of Staff, complained during his House testimony about the common practice of "repeated continuing resolutions, which hamper long-term investment and often result in increased costs."
The continuing resolution keeps the spending of defense programs at the previous year or lower, and it prevents the Pentagon from starting new programs. The CR also is frustrating for defense contractors because it makes it harder for them to plan ahead and also could delay the awarding of contracts.
Top Pentagon officials also have long complained about the mandated caps hurting the military. Analysts say, however, there's probably not enough votes to amend the Budget Control Act limitations. It would require at least 60 votes in the Senate, or about eight Democratic Senators to go along with it.
Many lawmakers are for increasing national defense spending and adding more funding for homeland missile defense, although they are resisting efforts by the White House to cut domestic programs as a way of boosting the military. President Donald Trump has proposed cuts to domestic programs such as Medicaid, food stamps, foreign aid and general science.
In all, the White House plan would increase defense spending by $54 billion, but do it by decreasing spending on non-defense programs by roughly the same amount.
Some believe the House and Senate will end up setting aside the Trump plan and coming up with a different agreement that doesn't have the steep domestic cuts.
"There's a deep fundamental divide between the Freedom Caucus members in the House, the more mainline conservatives in the House and the Senate, and the Democrats in the House and Senate," said Katherine Blakeley, a research fellow at the nonpartisan Center for Strategic and Budgeting Assessments.
Added Blakeley, "What exactly to do about defense spending is almost certainly going to get kicked down the road until about December," she said.
Last week, Trump said he planned to increase the defense spending "by many billions of dollars because of North Korea, and other reasons having to do with the anti-missile [defense]."
The president's comments about more anti-missile defense followed disturbing news that nuclear-armed North Korea may now have a long-range missile capable of threatening not only the U.S. West Coast, but eastern cities such as New York. Last month, the hermit regime test-fired its second intercontinental ballistic missile, with some Western experts estimating the July 28 launch showed the Hwasong-14 long-range missile could reach half, if not most, of the continental U.S.
"It is very easy to increase spending on missile defense because the government at present spends so little on it," said Loren Thompson, a defense industry consultant and chief operating officer of the Lexington Institute, an Arlington, Virginia-based public-policy think tank.
Thompson said spending on missile defense has actually been trending downward over the last several years. "The actual amount of money that the U.S. government spends on defense of the homeland against missile attack is less than $2 billion per year," he said.
The U.S. already has plans this year to add more interceptors to its current ground-based midcourse defense (GMD) system installed in Alaska and California.
A measure in the Senate has more than two dozen co-sponsors and would upgrade the GMD homeland missile defense shield and also order concept work on a space-based sensor layer that can track missile threats. Another plan, from Republican Sen. Ted Cruz of Texas, calls for a space-based interceptor system to defeat the nuclear threat from North Korea.