Updated

President Obama’s START Treaty is in trouble, and with every hour that passes it gets further away from ratification by this Congress. Time is running out, yet the president seems reluctant to answer his critics with anything more than non-binding words. At this point, he should take the Treaty off the table rather than risk its defeat. And when the new Congress considers the New START, President Obama would do well to consider how President Reagan approached arms control.

Reagan knew he would have to satisfy critics on the left and right who claimed that arms control treaties served American interests. Reagan’s theme? Trust But Verify.

Reagan showed the doves -- who thought the U.S. was just as much a threat to world peace as the Soviet Union -- that he was willing to stop the arms race and agree to deep reductions on strategic weapons.

He showed the hawks, who thought the Soviet Union could never be trusted, that verification had to be an essential part of any agreement.

Reagan didn’t just take the Soviet leaders’ word for it that they wouldn’t violate the treaty, his verification procedures guaranteed their compliance.

President Obama needs to do the same today, but with a slightly different twist -- Trust But Clarify.

The biggest problem with the New START treaty is its ambiguous language about missile defense. The Treaty's preamble seems to prohibit the U.S. from developing new missile defense systems in the years ahead, with vague wording about the “interrelationship between strategic offensive arms and strategic defensive arms” and the assertion that defensive arms not undermine the effectiveness of offensive arms.

Since Article V, Paragraph III of the treaty expressly forbids the conversion of existing launchers from offensive weapons to defensive interceptors and vice versa, it’s not a stretch to conclude that the Russians want to limit our ability to develop defensive systems in the years ahead. It would be cheaper to build new defensive launchers than convert existing offensive ones.

But the question still remains whether we would be free to build new defensive launchers under the Treaty. Indeed, the Russians have issued statements saying they would withdraw from the New START Treaty were we to do so, saying the U.S. must refrain “from developing its missile-defense capabilities quantitatively or qualitatively.”

President Obama has issued statements saying just the opposite, that the Treaty “places no limitations on the development or deployment of our missile defense.”

They can’t both be right. The unilateral Russian statements might be non-binding, but they are at odds with what President Obama and Secretary Gates have said about defensive systems. Such a fundamental difference of opinion between the Russian and American interpretations on such a key element of the Treaty must be cleared up before the Senate votes for ratification.

The doves aren't worried that the president has a trust deficit with Russians. But the hawks are worried -- that Obama is too trusting, to the point of naivete. They worry President Obama is so caught up in his vision of a nuclear free world that he’s willing to reduce U.S. arsenals unilaterally, or forego defensive systems, in hopes that others will follow our good example.

They see missile defense as essential to keeping America safe in the years ahead. Since we've failed to stop nuclear proliferation by rogue states, countries like North Korea or Iran could present an even greater threat down the road than Russia does today. They worry that an ambiguous treaty could tie the hands of future presidents by limiting our ability to develop defensive systems against developing nuclear threats.

If the president believes the New START doesn’t tie our hands on missile defense, he should take steps to clear up the ambiguities.

The best case scenario would be for the Senate to amend the treaty before ratification. This would, in all likelihood, mean that the U.S. and Russians would have to go back to the negotiating table. But the Senate could tack on a formal reservation to the treaty; or at a minimum allow a "Sense of the Senate Resolution" stating that the treaty does not prohibit either side from doing research and development and deployment of defensive systems. If the Russians balk at any of these, it’s a clear demonstration that they DO intend to limit our development of defensive systems, which would be unacceptable.

If the president is unwilling to take any of these steps, then one has to ask why not? Is President Obama afraid the Russians will walk away from New START, thus robbing him of his sole foreign policy accomplishment to date? If he believes a treaty is in America’s best interests -- because it allows our inspectors back into Russia and encourages the Russians to cooperate with us over Iran -- then isn’t it worth clearing up any ambiguity to get Senate ratification? The only thing worse than no treaty is a treaty that damages American security.

President Reagan understood this when he walked away from a flawed arms control treaty with Soviet President Gorbachev. In the end Reagan got the treaty he wanted and won the Cold War.

That’s the page President Obama needs to borrow from the President Reagan’s book. President Obama needs to clarify, in binding language, that New START doesn’t preclude our ability to develop defensive systems to deal with threats from emergent nuclear weapons states like North Korea and Iran.

If the Russians are unwilling to agree to such a clarification, President Obama should, like Reagan, be willing to walk away from a flawed treaty. If President Obama is unwilling to clarify the treaty, the Senate should walk away from him.

Kathleen Troia "K.T." McFarland is a Fox News National Security Analyst and host of FoxNews.com's DefCon 3. She is a Distinguished Adviser to the Foundation for the Defense of Democracies and served in national security posts in the Nixon, Ford and Reagan administrations. She wrote Secretary of Defense Weinberger’s November 1984 "Principles of War Speech" which laid out the Weinberger Doctrine. Be sure to watch "K.T." every Monday at 10 a.m. ET on FoxNews.com's "DefCon3" already one of the Web's most watched national security programs.