Senate Democrats on Thursday officially threw down the spending gauntlet, blocking consideration of the annual defense appropriations bill as part of a strategy to force Republicans to agree to greater funding levels for domestic programs.

Senate Democrats are promising to filibuster any fiscal 2016 spending bill until Republicans agree to renegotiate the budget caps put in place  in 2013 as a result of of the 2011 Budget Control Act, also known as the sequester.

The defense spending bill was the first test of the plan. In recent days GOP leaders have tried to pressure Democrats by arguing they are holding up money for the troops in order to win more spending for agencies such as the Internal Revenue Service.

But Democrats say they aren’t concerned about the politics of blocking military funding and believe that ultimately Republicans will have to come to the negotiating table.

“I think they thought they could win this vote and they haven’t,” said Sen. Charles E. Schumer (D-N.Y.). “I hope this vote convinces them that we want to sit down and negotiate, we don’t want to head to a crackup which is where they’re headed.”

Democrats successfully blocked the motion to begin consideration of the defense appropriations bill in a 50 to 45 vote, falling short of the 60 votes required to open debate. One Democrat, Sen. Joe Donnelly (D-Ind.), voted with Republicans.

The Senate Democrats’ plan has the backing of the White House and President Obama has vowed to veto spending bills that adhere to the Republican budget in an effort to boost funding for domestic programs, such as those concerning health research, environmental protection and law enforcement.

The next step in the spending stand-off remains unclear, but Republicans on Thursday said they weren’t going to budge.

Appropriations Committee member Sen. Roy Blunt (R-Mo.), told reporters that he wants to force Democrats to keep blocking bills so they can be blamed for obstructing the funding of the government.

“It is time for these bills to be on the floor and certainly my advice to [Senate Majority Leader Mitch McConnell (R-Ky.) ] would be to continue to bring the bills to the floor,” Blunt said. “Let the minority stand in the way of debating the bills and funding the government.”

Neither party particularly likes the spending cuts mandated by the sequester but Republicans are tapping a war funding account to allay their concerns about the impact of these caps on Pentagon programs.

McConnell has repeatedly vowed to fund the government through the regular order by passing a budget and voting on each of the 12 funding bills produced by the Appropriations Committee. Democrats are betting McConnell will be forced to abandon the strategy when it becomes clear regular order is impossible.

Schumer, Richard J. Durbin (D-Ill.), Patty Murray (D-Wash.) and Senate Minority Leader Harry Reid (D-Nev.) wrote to McConnell ahead of the vote to reiterate that goal.

“Simply put, sequestration was — and still is — a mechanism that is supposed to precipitate bipartisan negotiations,” they wrote. “We respectfully request you schedule the first round of these important negotiations as soon as next week.