Democrats are threatening an aggressive confrontation with Republicans over federal highway money, foreshadowing yet another round of brinkmanship with the GOP and raising the specter of a temporary shutdown of transportation construction sites nationwide.

House and Senate Democrats are weighing a hard-line strategy that would force Republicans to stumble through a series of painful short-term highway extensions if they don’t fix the program’s long-term funding woes, with the Highway Trust Fund slated to run out of money after July 31.

Democrats have long insisted that Congress needs to put the highway fund on firm financial footing for years to come, but bipartisan antipathy to new taxes has produced a series of stopgaps and patches under the leadership of both parties.

“I think it’s horrible that they’re even thinking about the short-term extension,” said Senate Minority Leader Harry Reid (D-Nev.) in an interview. “I think it’s ridiculous.”

Unless Republicans can come up with tens of billions of dollars in new tax money or spending cuts, the GOP could be forced to acquiesce to Democratic demands or risk a shutdown of infrastructure projects in the middle of the summer construction season. Still, the strategy could also blow up in Democrats’ faces, as the GOP is sure to paint them as obstructionists, particularly if a shutdown comes to pass in July.

The goal, Democratic sources said, is to expose the GOP’s lack of planning ahead of the July deadline and pressure them to come up with as much as $90 billion for a six-year transportation bill just at flat funding levels, a near impossibility without politically painful tax increases. The most aggressive tactic, raised by Senate Minority Whip Dick Durbin (D-Ill.) at a private bicameral leadership meeting Tuesday, would have Democrats filibuster any transportation funding extension lasting longer than 30 days.

Democratic leaders are now shopping the idea to their chairmen and the rank and file to test just how far the party is willing to press Republicans on an issue that’s sharply divided the GOP.

The early returns inside the Democratic leadership meeting were positive, sources said, suggesting Democrats will force a showdown over the looming transportation cliff.

“They’re nothing but trouble,” said Senate Majority Whip John Cornyn (R-Texas). “They’re just feeling a bit feisty and cantankerous.”

“They’re going to try to jam us on everything,” added Sen. John Thune of South Dakota, the No. 3 GOP leader.