Senator Robert Menendez fired back at a Republican letter that pressed for a vote on his Iran-sanctions legislation.
Under Menendez's bill, additional sanctions would be levied against Iran if it walks away from the interim agreement over its nuclear program, or talks over a long-term deal. Iranian officials have said such legislation, or any sanctions legislation, would kill diplomatic progress.
"I have long thought of this as a bipartisan national security issue -- not a partisan political issue," the New Jersey Democrat said. "And -- at the end of the day -- a national security issue that we must approach in a spirit of bipartisanship and unity, which has been the spirit for which we have worked together on this matter. And I hope that we will not find ourselves in a partisan process trying to force a vote on a national security matter before its appropriate time."
Forty-two Republicans sent a letter to Senate Majority Leader Harry Reid on Tuesday calling for a vote during the current work period on Menendez's proposal. That would require a vote on the bill next week, with the Senate expected to start its next state-work period on Feb. 17.
In the letter, uploaded by the Daily Beast, Republicans say it is the Obama administration that is turning a historically bipartisan issue into a partisan one, and hits at Reid for taking "unprecedented steps to take away the rights of the minority in the Senate."
Republicans have continued to speak out against Reid's decision to "go nuclear" last year, and the two sides have frequently gotten bogged down in fights over amendments to legislation.
The sanctions bill has 58 cosponsors, 15 of whom are Democrats and 43 are Republican. Of the 15 Democratic cosponsors, two signed on after Dec. 19 -- the day the bill was introduced.
Under the interim agreement reached by six countries with Iran in November, the country curbs its nuclear program in exchange for limited sanctions relief.
Menendez said he remains deeply concerned about Iran, noting that officials "say one thing behind closed doors in Geneva, and say another thing publicly."
And he called the one-year sanctions delay included in his proposal "significant and generous given Iran's history of treachery and deceit."
But whether or not sanctions legislation will come up for a vote in the Senate rests with one person -- Reid, who has frequently avoided being pinned down on if, and when, he would bring such a proposal to the floor.
The Nevada Democrat said last month that he would "wait and see" about legislation.