President-elect Donald Trump in late December at his Mar-a-Lago estate in Palm Beach, Fla. (Evan Vucci/AP)

President Trump’s plan to fund the government after April 28 would add to the deficit, testing GOP fiscal hawks who vigorously opposed deficit spending during the Obama administration.

Trump’s Office of Management and Budget has proposed that the government spend an additional $30 billion on military operations and $3 billion more for border security for the period between April 29 and Sept. 30. The OMB has recommended $18 billion in cuts — to social and educational programs and others — to offset the new $33 billion in spending, but the changes would still widen the deficit by $15 billion.

Congress has agreed to fund the government only until April 28, and a partial government shutdown will occur on April 29 if there is not an agreement.

The Congressional Budget Office has projected the U.S. government will run a deficit of $559 billion for this fiscal year. The deficit is the annual gap between spending and revenue. If the government can’t cover all of its spending with revenue, it needs to borrow more money by issuing debt. The more debt the government issues, the more interest it has to pay on that debt, and the costs grow and pile up.

Many Republicans oppose raising taxes to reduce the deficit, but they have also said the deficit must be eliminated. This means Trump’s new budget request forces them to make tough choices. If a bloc of Republicans won’t agree to Trump’s spending proposal, which increases the deficit, the spending bill won’t pass the House or Senate without support from Democrats.

But Democrats have said they won’t vote for a spending bill that includes new money to build a wall along the U.S. border and cuts spending for social programs.

If all Democrats oppose the spending bill and a bloc of Republicans refuse to vote for anything that increases the deficit, how will Trump find the votes to avoid a shutdown?

He won’t.

Congressional leaders are experts at walking this tightrope, and they still have plenty of time to cut a deal. But they have several factors that make this more perilous.

First, the collapse of the GOP's health-care bill in the House has splintered Republicans and led to plenty of finger-pointing. Democrats see a president with low approval ratings and have expressed little interest in cutting a deal.

There have been 12 government shutdowns since 1980, six of which lasted just one or two days. But there has never been a shutdown in that period that occurred when one party controlled the White House, the House and the Senate.

That should make it easier to avoid a shutdown, but Trump has campaigned on big cuts in spending. If he abandons his call for spending cuts, it could embolden Democrats to oppose more of his agenda. But if he doesn’t call for enough spending cuts, the conservative House Freedom Caucus could reject the plan. It routinely opposed spending bills during the Obama administration, and its members frequently say they will not support any spending bill that widens the deficit.

The Obama administration escaped this scenario multiple times because Democrats stepped in and joined Republicans to help the bills win passage. There’s a good chance that might not happen this time.