President Barack Obama's Republican foes in the US Senate warned him Friday to drop plans to repeal a military ban on gays serving openly or risk the fate of a landmark nuclear part with Russia.

Republican lawmakers who had previously indicated support for the new Strategic Arms Reduction Treaty (START) expressed anger at key procedural votes Saturday on the "Don't Ask Don't Tell" prohibition and an immigration measure.

Democratic Senate Majority Leader Harry Reid's decision to push ahead with both proposals, which are fiercely opposed by Republicans, came with the White House on a quest for Republican support necessary to ratify the treaty.

Republican Senator Bob Corker, who has played a key role in debates on the accord, one of Obama's top foreign policy priorities, said Reid's move "poisons the well on this debate on something that's very, very important."

"I'm hoping that those will be taken down or I don't think the future of the START treaty over the next several days is going to be successful, based on what I'm watching," in meetings with fellow Republicans, he warned.

In response, Democratic Senator John Kerry, chairman of the Senate Foreign Relations Committee, said "my hope is that everybody will simply rise above whatever, however they want to view these votes."

Number-two Senate Republican Jon Kyl, his party's point man on the treaty, seemed to echo Corker when asked whether there was any connection between the treaty and the repeal vote.

"The only linkage is that the problem of having all of these political votes is that it certainly doesn't help create an atmosphere of cooperation on other issues," he said.

The DREAM Act, aimed at helping children of undocumented immigrants stay in the United States, was expected to fail its procedural test, but Democrats were thought to have the 60 votes to move forward with the repeal.

Obama's defeated Republican White House rival, Senator John McCain, accused Reid of setting up votes aimed at energizing core Democrats for "political advantage" and warned Republicans were "just growing weary" of such maneuvers.

But McCain stopped well short of tying the treaty to the Saturday votes, and spokeswoman Brooke Buchanan said he "will base his support on START on the merits of the treaty" and his efforts to address his concerns about it.

Republican Senator Lindsey Graham flatly denied a news report that he has told the White House the decision to put the repeal to a vote had cost them his support on START, telling reporters: "That has never been true."

But Graham called the Saturday votes "offensive" and quipped "the lame duck is beginning to smell up the place" -- using the common term for a year-end legislation session after an election -- and warned the White House may face a "consequence" on the treaty for its approach.

The fight came as leading Republicans worked to force a final vote off to next year or effectively kill the treaty by amending it.

In one such gambit, Republicans pushed to modify the treaty's non-binding preamble to strike language tying offensive nuclear weapons to defensive systems, an unmistakable reference to US missile defense plans.

The agreement -- which has the support of virtually every present and past US foreign policy or national security heavyweight -- restricts each nation to a maximum of 1,550 deployed warheads, a cut of about 30 percent from a limit set in 2002, and 800 launchers and bombers.

The accord would also return US inspectors who have been unable to monitor Russia's arsenal since the treaty's predecessor lapsed in December 2009.

Asked about the Republican warnings, Senate Armed Services Committee chair Carl Levin, a Democrat who has played a key role in both matters, replied: "I would hope they wouldn't do that. I mean we ought to pass them both."

And pressed on which of the two issues he would give up, Levin replied: "I'm not choosing between my children."