NEW START INCHES FORWARD, BUT OUTCOME STILL IN DOUBT…. Opponents of the pending nuclear arms treaty, New START, know they don’t support the agreement, but they’re having a little trouble explaining why. They keep bringing up new complaints, all of which are easily debunked and proven baseless.

During the floor debate yesterday, one of the points that kept coming up is the notion that there just isn’t enough time in the lame-duck session for a thorough discussion. It led Senate Foreign Relations Committee Chairman John Kerry (D-Mass.) to raise a good point.

“We have now spent 5 days having a very good debate on New START and proposed amendments. That is as much time as the Senate spent on START I, and more than it spent on START II and the Moscow Treaty combined, but we are looking forward to continuing the debate this week,” Kerry said in a statement Sunday evening. “This is a big test of the Senate because this treaty is about our national security, not our politics. Our country and the world have watched a spirited exchange of views in the best traditions of the Senate, and there is more to come as we work to address senators’ concerns.”

Let no one say Democrats are “jamming” this through without sufficient debate.

Indeed, Republicans have been free to bring forward sweeping amendments, including measures that would kill the treaty. On Saturday, a poison-pill amendment offered by Sens. John McCain (R-Ariz.) and John Barrasso (R-Wyo.) failed, and a related push from Sen. James Risch (R-Idaho) yesterday fared even worse.

The good news is, these amendments haven’t come close to passing. The bad news is, far-right senators might use this as an excuse to scuttle the entire initiative and undermine U.S. foreign policy.

As of yesterday, several key Republicans announced their opposition to the treaty — for reasons ranging from odd to dumb — and the outcome remains in doubt.

The top two Senate Republicans declared Sunday that they would vote against President Obama’s nuclear treaty with Russia as the bipartisan spirit of last week’s tax-cut deal devolved into a sharp battle over national security in the waning days of the session.

With some prominent Republicans angry over passage of legislation ending the ban on gay men and lesbians serving openly in the military, the mood in the Senate turned increasingly divisive and Mr. Obama and Democratic lawmakers scrambled to hold together a coalition to approve the treaty.

I continue to find this astounding. Republicans are “angry” that Democrats passed a bipartisan bill requested by the Pentagon and endorsed by the vast majority of Americans, so they’re prepared to defeat a treaty that military leaders consider vital to our national security?

The Senate is no place for petulant children.

It’s probably a lost cause, but the Republicans’ handling of this debate really should generate a wholesale reevaluation of which party has earned credibility on foreign policy and international affairs.

Regardless, a cloture vote will likely be held tomorrow. The Senate leadership is still eyeing a ratification vote for this week.

Steve Benen

Follow Steve on Twitter @stevebenen. Steve Benen is a producer at MSNBC's The Rachel Maddow Show. He was the principal contributor to the Washington Monthly's Political Animal blog from August 2008 until January 2012.