WASHINGTON — In an ironic legislative twist, the broad-based bipartisan support in Congress for the Iron Dome project turned an urgent request for additional funds into a political hot potato, trapping efforts in Washington gridlock Thursday. Israel requested an additional $225 million for the partially US-funded project, which is credited with saving dozens, possibly hundreds, of lives, but partisan ploys prevented Congress from approving the funding before it adjourns for a month-long recess.

Although pro-Israel legislation tends to be greeted with broad bipartisan consensus, in recent days emergency funds for Israel have become a political weapon wielded rhetorically by both parties in their attempts to tar each other. As a result, the effort — supported by both Democrats and Republicans — to approve the supplemental funding is likely to prove fruitless before Congress reconvenes in September.

Both houses of Congress were originally slated to adjourn for a month-long recess Thursday, but House Republicans said that they would continue to convene until they passed a bill funding additional steps to stem the tide of immigrants crossing America’s southern border. The Senate continued meeting well into the night Thursday, but leadership did not indicate any intention to extend the legislative session.

Israeli defense sources did not give Congress a specific time frame regarding the urgency of the additional allocation, but Iron Dome intercepts over the course of Operation Protective Edge have likely cost Israel tens of millions of dollars.

Both sides of the aisle have emphatically stated their support for additional funding for the system — and because support is so strong, it has proven to be a powerful tool to malign the opposite side in an ongoing budget fight in the last hours of the Congressional session.

The Democrat-controlled Senate included the $225 million in a $3.5-billion emergency supplemental spending bill, which it began to advance on Wednesday, but blocked late Thursday when it failed on a procedural vote. That bill had evoked the ire of Republicans by providing extensive funding for an administration immigration policy opposed by most Republican legislators. In opposing the bill, Republicans argued that it failed to address the root causes of America’s current influx of Central American children seeking asylum along the southern border.

The Senate bill was a non-starter in the House because of the immigration issue — a push-button topic for Republican rank-and-file. At the same time, the administration heartily opposed separating the Iron Dome funding from the rest of the supplemental spending — possibly because it put Republicans in a catch-22 situation: With some 70% of Republicans supportive of Israel, Republicans would be forced to choose between voting for the administration’s immigration funding, which their voters likely oppose, and voting for the additional funding for Israel; or voting against the supplemental bill, which Democrats could spin as a vote against providing Israel with the additional Iron Dome funds.

Last week, a frustrated Sen. John McCain (R-AZ) said that if the funding was presented as a stand-alone bill, the Senate “could take up $225 million on the floor of the Senate by unanimous consent today.

“It would pass without objection,” he argued.

But when the funding was presented as a near-stand-alone late Thursday, the measure still did not pass.

Senate Majority Leader Harry Reid finally acquiesced to split the funding together with $615 million to fight wildfires from the immigration budget. Republicans, however, rejected that move as well. Minority Whip John Cornyn (R-TX) indicated that he would not approve such a measure, while Sen. Tom Coburn (R-OK) suggested a compromise to offset the combined total of $840 million in additional spending with spending cuts to the United Nations and other international organizations.

Reid, in turn, rejected Coburn’s suggestion.

Partisan politicking over the funds has built up in the past week. The White House used the Iron Dome funding issue to disparage HR 5230, the Republican proposal for supplemental appropriations to finish out the 2014 fiscal year. Among its handful of major critiques of the bill, the White House complained in a rare statement Wednesday that “HR 5230 does not include funding for the Department of Defense to support the Government of Israel’s request for critical missile defense needs.”

Speaking later on Wednesday, White House Deputy Spokesman Eric Schultz affirmed that “part of our commitment to working with the State of Israel is the significant resources we’ve done on the Iron Dome to help Israel protect its citizens.”

“Obviously, there’s an additional request pending in front of Congress, and we hope they move on that,” Schultz told reporters.

The House of Representatives was, in fact, moving. By Wednesday afternoon, the House Foreign Affairs Committee passed the Emergency Iron Dome Replenishment Act, introduced by the Committee’s Ranking Member, Rep. Eliot Engel (D-NY), to provide additional funding for the missile defense system.

“By passing this important legislation, we send a strong message of support for our ally Israel and we ensure that the Iron Dome system is well-supplied and equipped to handle future threats,” Royce wrote in a statement.

Although the legislation was sponsored by a Democrat, the stand-alone funding legislation for the Iron Dome made life easier for Republicans who sought to provide support for Israel without approving a lengthier bill that would also include additional funding for immigration programs that they oppose- the legislation that the administration would have liked to see in place of HR 5230.

A boy next to a stop sign in front of an Iron Dome anti-missile battery near Tel Aviv. (photo credit: Roni Schutzer/Flash90)

A boy next to a stop sign in front of an Iron Dome anti-missile battery near Tel Aviv. (photo credit: Roni Schutzer/Flash90)

The Republicans pulled its larger supplemental spending bill early Thursday morning out of fears that they did not have the votes to pass it, and Hill staffers said that Engel’s bill for Iron Dome funding was pulled together with it.

But in a last-minute end-of-session drama, the House Republican leadership announced Thursday afternoon that they would stay in session until they passed the stand-alone bill for additional immigration spending.

Staffers close to the legislation said, however, that even with the extended session, the likelihood that any funding would come through before the recess was infinitesimal.

In order for the funding to be approved, the Senate would have to move quickly to pass its own funding bill, and the House and Senate bills would have to be reconciled before the Senate goes on recess.

The chances that there will be a special recess session convened to pass the Iron Dome funding before September were assessed as “zero” by one person close to the legislation.

For Sen. Mitch McConnell (R-KY), the Iron Dome has proved to be an unanticipated boon.

Last week, the Senate Minority Leader placed the blame for stalling the funds on Democrats, saying in a floor speech that “we hope our friends on the other side will join us in coming to a sensible, bipartisan solution that can be passed quickly” – implying that any failure to pass the additional funding was due to a lack of bipartisanship among Democrats.

But McConnell, who is facing a tough race for his seat in November received an unanticipated bonus when his Democratic challenger, Alison Grimes flubbed a question on the weapons system on national television.

“The Iron Dome has been a big reason why Israel has been able to withstand the terrorists that have tried to tunnel their way in,” Grimes was quoted as saying during an interview with Lexington Herald Leader.

Republicans have seized on Grimes’ comment to discredit the Democratic candidate as inexperienced in international affairs. For McConnell, who was losing to Grimes in the polls until mid-July, any added ammunition against his opponent could help buffer his slim two-point advantage.

Despite the partisan mudslinging over Iron Dome, a source at a pro-Israel organization said Thursday that “while it is sometimes difficult for Congress to pass legislation in the final days before the recess, there is very solid bipartisan support for the additional Iron Dome funding.”

The source said that given the support, “there is a strong reason to be optimistic that the funding will be approved when Congress returns In September.”