Congressional leaders remain preoccupied with health-care legislation this week, but a budget showdown is looming this fall that could lead to a government shutdown.

Earlier this week, the House Appropriations Committee introduced a bill to fund Homeland Security at the administration’s requested level of $1.6 billion for the next fiscal year. That money would help fund the border wall that President Trump campaigned on last year. Though money for the wall along the U.S.-Mexican border is a non-starter for congressional Democrats, conservative House Republicans are urging House leaders not to cave on funding for the wall – even if it means shutting down the government.

Rep. Mark Meadows (R-NC), chairman of the Freedom Caucus, said earlier this week that there are enough conservative votes to stop any budget deal in the House that does not fund Trump’s wall along the Mexican border.

“Without a doubt there are enough conservative members who will not support any funding mechanism that does not include border wall funding,” Meadows said.

Congress is expected to begin budget talks this summer. Current funding runs through the end of the fiscal year on Sept. 30. Wall funding was brought up this past spring as well, but congressional leaders had no appetite for a potential shutdown and came together on a $1.1 trillion funding bill for the rest of FY17.

For now, work is grinding along in the House and Senate Appropriations committees, with a number of spending bills to fund government agencies in 2018 approved this week.  Unlike health-care or potentially tax reform, however, a budget deal is almost certain to require Democratic support in order to pass.

Sen. Tom Carper (D-DE), a senior member and former chairman of the Senate Homeland Security and Governmental Affairs Committee, told POLITICO this week that “there’s no way” funding for a border wall will get 60 votes in the Senate this fall. Carper said Homeland Security officials have told him they have far more pressing needs than a border wall. “They’re not telling me they need a wall,” Carper said.