An unlikely duo of senators plans to make a last-ditch attempt next week at heading off a showdown between the White House and Congress over funding for fighter jets that the Pentagon doesn't even want. 

Against the advice of the Defense Department and President Obama, the Senate Armed Services Committee last month approved an additional $1.75 billion for seven extra F-22 fighter jets in the defense spending bill. 

But Sen. Carl Levin, D-Mich., and Sen. John McCain, R-Ariz., the chairman and ranking member of that committee, are trying to strike that money before the bill gets anywhere close to the president's desk. Obama has threatened to veto any legislation that includes money to buy more F-22 jets beyond the 187 requested. 

The Levin-McCain amendment could represent the last chance to avoid a showdown with the White House. And passions are high on both sides. 

"We have to deal with the decision of the Armed Services Committee ... to add F-22 planes, which uniformed and civilian leaders of the military indicate they do not want and do not need and we cannot afford," Levin said on the Senate floor. 

McCain accused F-22 backers of trying to commit millions in taxpayer dollars for the sole purpose of creating or saving jobs. 

Sen. Saxby Chambliss, R-Ga., who pushed for the extra jets and whose state would lose at least 2,000 jobs should the cap be imposed, said the debate is not just about job losses. 

"This is a debate about the national security of the United States of America," he said. "It is regrettable the administration needs to issue a veto threat for funding intended to meet a real national security requirement that has been consistently confirmed by our uniformed military leaders." 

A vote is expected Monday on the amendment to the defense bill, after Levin temporarily withdrew the provision Wednesday so that the Senate could first address a hate crimes bill. The Senate voted Thursday to attach that legislation, which would extend federal protections to people attacked because of their sexual orientation or gender, as an amendment to the $680 billion defense spending bill. 

Senate Majority Leader Harry Reid supports the Levin-McCain amendment, but is struggling to whip up the votes to push it through. 

On the House side, lawmakers also voted to add a $369 million down payment for 12 additional F-22 jets, in defiance of the White House. 

"I don't want to see the (production) line shut down," said Rep. John Murtha, D-Pa., chairman of the House Appropriations defense subcommittee. "If you're going to be prepared, you better not shut down the line." 

Murtha predicted the F-22 addition would make it through committee, but said there could be a similar confrontation in the full House if someone puts up an amendment like the Levin-McCain measure. 

Obama and Gates have taken an increasingly firm tone against Democrats and Republicans trying to push F-22 jets on the military. 

"We do not need these planes," Obama said in a letter to senators Monday, pledging to veto a bill that doesn't follow his guidelines. 

"It is time to draw the line on doing defense business as usual," Gates said during an address in Chicago Thursday. "The president has drawn that line. And that red line with regard to a veto is real." 

If Obama vetoes the defense bill, it would be the first veto of his presidency. It is unlikely Congress would have enough votes to override. 

The Associated Press contributed to this report.