If President Obama had more credibility on national security issues, this effort to amend the START treaty's preamble that contains ambiguous language about our ability to build a missile defense in Europe would probably have not been an issue.

That's because the language was left vague for a reason; both sides being able to interpret the codicil to their own advantage. Plus, there is a question how binding the preamble is as far as interpretation.

Nevertheless, given the president's long standing opposition to missile defense of any kind, the GOP is correct in requesting guarantees from the administration on how we will interpret the language of the treaty.

New York Times:

The vote came shortly after a letter from Mr. Obama was read in part on the Senate floor reaffirming his support for missile defense. Mr. Obama said the treaty "places no limitations on the development or deployment of our missile defense programs" and dismissed Russian warnings that it might withdraw from the treaty if American plans ultimately evolve into a threat to Russia's nuclear deterrent.

"Regardless of Russia's actions in this regard, as long as I am president, and as long as the Congress provides the necessary funding, the United States will continue to develop and deploy effective missile defenses to protect the United States, our deployed forces, and our allies and partners," Mr. Obama said in the letter.

At issue in Saturday's vote was an attempt by Senator John McCain, Republican of Arizona, to delete a clause in the treaty preamble that says the two sides recognize "the interrelationship between strategic offensive arms and strategic defensive arms" and "this interrelationship will become more important as strategic nuclear arms are reduced."

Obama administration negotiators have said such language was intended as a nonbinding gesture to Russian concerns about missile defense after American negotiators rejected any meaningful limits in the treaty. Defense Secretary Robert M. Gates and the nation's top generals have said the preamble language would not constrain missile defense.

Given the vote of 59-37, Obama is still coming up short votes to ratify the treaty, two-thirds of those voting needed to pass it. Technically, they probably have the votes already, but Obama's lack of credibility on defense and national security is causing some GOP senators who might otherwise be persuaded to vote in favor to hold off for similar guarantees on force modernization. Obama claims to have answered all concerns of GOP senators but that is obviously not the case. Whether he can do so before the senate adjourns for Christmas remains to be seen.