Senate Democratic Leader Harry Reid is already warning that GOP tactics will lead to another government shutdown this fall.
"It appears to me, [with] what the Republicans are doing that we're headed for another shutdown," he said on the Senate floor Wednesday morning. "They did it once. They're going to do it again. They don't want to do anything now. They want to wait until the fiscal year ends and then lock it up. Close up government."
Democrats recently announced their plan to obstruct all of the Republicans' spending bills, which comply with across-the-board cuts signed in a 2011 budget law known as "sequestration." If Congress can't pass an appropriations package by the end of September, the government will shut down, as it did in 2013 over Republicans' objections to the implementation of Obamacare. The new GOP-led Senate—despite passing several significant bills on free trade, human-trafficking, and Iran nuclear negotiation oversight in the first half of the year—could grind to a halt.
Many Republicans are willing to break sequestration's budget caps, but only for the military. Senate Armed Services Chairman John McCain is leading a defense authorization bill on the floor that sidelines the budget law by boosting a separate war account by $38 billion, bringing the GOP budget in line with the president's, who adds the money into the base funding. Even McCain sees the move as a gimmick, but one he thinks is necessary to adequately fund the security of the country.
Now Democrats want to use their best tool in the minority—filibustering—to bust the budget caps for domestic programs as well.
"Like ostriches with their heads buried deep in the sand, the majority leader and Republicans continue to deny the need for a bipartisan budget," said Reid.
It's unclear if the standoff will actually lead to a government shutdown. House Majority Leader Kevin McCarthy has said that the caps "will hold" and Senate Republicans are skeptical that Democrats will block the defense authorization bill, a historically bipartisan measure that has passed for the past 53 consecutive years.
"At a moment of dangerous and gathering threats, here's the position of these Democratic leaders: They want to hold hostage the funding needed to make our troops combat-ready so they can spend more on bureaucracies like the IRS," said Senate Majority Leader Mitch McConnell on the floor Wednesday. "These Democratic leaders just can't seem to kick the gridlock habit, even on legislation with the exact same level of funding President Obama asked for in his own budget."
Some lawmakers are already planning for a potential shutdown. A group of senators is pushing legislation that would keep the National Parks open even if the rest of the government closes.
Alex Rogers covers Congress as a staff correspondent for National Journal. He previously worked as a political reporter at TIME. He is a native of Bethesda, Maryland and a graduate of Vanderbilt University.