The spending level for defense in the coming year is all but locked in, but that does not mean attempts to increase the Pentagon’s budget are dead.

House Majority Leader Eric Cantor of Virginia raised some doubt Thursday about the GOP commitment to the split between defense and nondefense spending in fiscal 2015 that Congress agreed to last year. In a floor colloquy, Cantor would not say whether the House budget resolution would raise defense spending at the expense of nondefense spending.

Lawmakers and aides said later that House Budget Chairman Paul D. Ryan is sticking with the terms of the budget agreement he negotiated with Sen. Patty Murray, despite speculation that Republicans may break the “firewall” on spending.

But the public exchange between Cantor and Minority Whip Steny H. Hoyer, D-Md., served as a reminder that ardent defense backers aren’t giving up on efforts to boost the defense budget.

Cantor made the case for that in his floor exchange, pointing to events “going on in the world right now” that he said demonstrated “very strongly for the need for American military power and our ability to project that.”

Ryan asked White House Budget Director Sylvia Mathews Burwell at a recent hearing whether the Obama administration would consider shifting discretionary spending to defense, but she said the administration believes money should be added to both defense and domestic programs.