President Obama's plan to share classified data on our missile defense system with Russia should be blocked by Congress.

The head of the Pentagon's Missile Defense Agency, Vice Adm. James Syring, disclosed these plans in congressional testimony last week. He also reportedly said that, while the MDA had some internal discussions about the plan, nothing as yet has been declassified or turned over to the Russians.

Obama has already taken unprecedented steps on missile defense in the strategic arms limitation agreement with Russia that was ratified by the Senate in late 2010.

There, for the first time, he allowed Russia to link missile defense with arms limitations. The Russians, evidencing a concern with missile defense that borders on paranoia, had sought that linkage since President Reagan announced the first Strategic Defense Initiative in 1984.

Since President George W. Bush canceled the Anti-Ballistic Missile Treaty with Russia in 2001, the Russians have been seeking ways to cut into our missile defenses, as well as those of Europe.

Now, Obama seems to be giving them what they want, and eagerly so. He has broken Bush's promise to Poland of a land-based defense, promising instead a yet-to-be-delivered sea-based system. Just last year, he canceled the final part of the European system that would have targeted ICBMs.

Sharing classified data with Russia on missile defense capabilities will devalue the system's ability to function by giving a potential adversary information on how to defeat it.

To share such data with Russia or any other potential adversary necessarily has that effect. And Russia has removed the "potential" from the term "potential adversary."

How else could you characterize a nation that is heavily engaged in building Iran's nuclear program, supports the Assad regime in Syria and challenges us in virtually every other corner of the globe? Russia's opposition to American policy around the globe is something in which its government takes pride.

Second, Russia will certainly be a more aggressive opponent as long as Vladimir Putin and his ilk are in power there. That Russia's nuclear arsenal could be turned on us again is reason enough to deny Putin data on our missile defense systems that could defeat them.

And, third, there is the likelihood that Russia would share what it learns with other adversaries. What guarantee could Russia give that it wouldn't share the missile defense data with, say, North Korea or Iran? To ask the question is to answer it: It couldn't give a guarantee that was worth anything.

The idea of sharing missile defense secrets with the Russians is baffling. What purpose could Obama want to achieve through it other than neutering the systems that provide a huge element of American security?

Obama's drift toward Russia is a little more than alarming. When Secretary of State John Kerry is left cooling his heels for three hours while awaiting an audience with Vladimir Putin, we puzzle at what we're trying to achieve.

When the State Department says we're trying to organize a peace conference on Syria -- with Russia -- the puzzle seems to be solved. We're letting Russia lead in the Middle East, and Putin won't hesitate to push us into the back seat.

To defend America against nuclear attack is a moral imperative. No one, other than an aggressor, should have any objection to missile defense because that defense does nothing to endanger the potential aggressor.

Rather than disclosing our missile defense secrets, the president should be demanding to know why Putin is so adamant in condemning a purely defensive system that doesn't endanger Russia.

Several Republicans in both the House and the Senate are reportedly planning to try to block the data disclosure. It is urgent that they succeed.

Examiner contributor Jed Babbin was appointed deputy undersecretary of defense by President George H.W. Bush. He is the author of such best-selling books as "Inside the Asylum" and "In the Words of Our Enemies."