(AP Photo/Pablo Martinez Monsivais)
President Barack Obama pauses after speaking to members of the media during his meeting with Baltic leaders in the Cabinet Room of the White House in Washington, Friday, Aug. 30, 2013. Russia has been a steady roadblock against any international condemnation of Syria’s ruling regime, standing in the way of United Nations action critical of Syrian leader Bashar Assad.

Russia has been a steady roadblock against any international condemnation of Syria’s ruling regime, standing in the way of United Nations action critical of Syrian leader Bashar Assad.

Syria, meanwhile, has consistently denied it used chemical weapons on its own citizens, or that it possesses any chemical weapons at all.

These two things are important backdrops to the latest diplomatic opening to avert a U.S. attack on Syria — an opening that now has Syria apparently acknowledging it does, in fact, possess such weapons.

There are plenty of reasons to be optimistic about Russia’s sudden willingness to urge Syria to turn these weapons over to the international community and to eventually have them destroyed. But there are just as many reasons to be skeptical of the offer and to insist on tough and thorough verification procedures.

This potential breakthrough started with an apparently off-hand remark by U.S. Secretary of State John Kerry in response to a reporter’s question. He said the current crisis could be defused if Syria agreed to hand over all its chemical weapons to the international community. Russia appeared to surprise the United States by quickly responding it was willing to push for such an outcome, prompting Kerry initially to say it had not been a serious proposal. Some U.S. lawmakers, however, responded by saying such a thing could diffuse a tense situation — not just between the United States and Syria, but also between President Obama and Congress.

The benefits of such a deal should be obvious. A new CNN/ORC International poll shows Americans are widely opposed to a military strike against Syria and do not believe it would accomplish any of the nation’s goals. Obama faces a difficult uphill climb convincing members of Congress to support a resolution authorizing a strike, especially considering it would require many lawmakers to vote against the wishes of their constituents.

A resolution that effectively disarms Syria as far as chemical weapons are concerned could save face internationally for the United States, which has struggled to get support from its allies for military action. It also would remove the question of whether such a strike would place the United States in a position of supporting rebel factions that may be closely aligned with the terrorists it has been fighting since 9/11.

And yet the actors involved are far from trustworthy. If the Obama administration were to consider this diplomatic avenue, it must insist on credible verification, and the president should press ahead with congressional authorization to use military force, which would give him powerful leverage. For its part, Congress should be more open to such authorization with such a process underway.

As we said last week, the United States has little choice but to retaliate against Syria for such widespread use of chemical weapons. The attack put U.S. allies at risk in various ways, which makes it a matter of national interest. In addition, the United States has an interest in helping the world draw an important line against the use of such weapons.

Whether or not the administration chooses to act on Russia’s offer, Obama faces a challenging week. He must present credible evidence that Syria used chemical weapons, and he must find ways to persuade both the American people, in an address tonight, and their representative in Congress that military strikes are necessary.

The outcome could set the tone for the rest of his second term.