The days ahead could define the presidency of Barack Obama as he goes first to Moscow then to Capitol Hill seeking approval for U.S. military intervention in the Syrian civil war.

The conflict has endured two and a half years, resulting in more than 110,000 deaths and the displacement of millions into refugee camps in neighboring Turkey, Jordan, Lebanon and Iraq. Israel is Syria’s other neighbor in the always volatile Middle East.

While essentially a civil war, the conflict has multinational undertones including its birth amid the “Arab Spring” revolts that toppled dictatorships in Egypt, Yemen, Tunisia and Libya. An earnest longing for political independence accompanied the Arab Spring movement. So did a strong desire for sharia law, flavored with an al-Qaida influence.

Last month, Syrian President Bashar al-Assad crossed a proverbial red line, Obama says, when he reportedly authorized use of a nerve gas — a weapon of mass destruction — against his own citizens, killing more than 1,400 people. The clear violation of an international ban must be met with an international response, Obama says, and the U.S. is prepared to deliver it — alone, if necessary but preferably with multinational backing.

Obama’s proposed attack most likely would take the form of strategic missiles launched from U.S. warships clustered hastily in the Mediterranean Sea. The missiles’ targets have not been identified.

Obama will need to be meticulous in his persuasion. He must show how an attack would protect U.S. vital interests in the region. That’s a difficult premise in a civil war pitting a bloody, anti-U.S. dictator against rebels backed by the equally anti-U.S. al-Qaida. Favoring either faction would not be in America’s interests.

Obama also has assured the public the U.S. would not get bogged down in another foreign war that it can’t afford.

In Moscow, Obama will encounter his most strident skeptic in Russian President Vladimir Putin, who is hosting a summit of 20 national heads of state. Putin has little respect for Obama and has done the most in international circles to thwart any international action against Assad.

Russia also occupies a permanent seat on the United Nations Security Council and, along with China, is likely to block any attempt to impose UN action against Syria.

Putin isn’t the only skeptic. News reports draw attention to a divided Congress and their constituents demanding more information.

Butler’s congressional representative, Mike Kelly, issued a statement Saturday welcoming “a rigorous debate” when the House reconvenes next week, adding, “Between now and then, I expect President Obama to adequately answer all of the lingering questions that Americans still have, and fully explain the defined objective of an American military strike, the precise strategy for carrying it out, and how it involves our national security interest.”

Kelly also encourages constituents across his Third District to share their opinions with him. That appeal has merit. Kelly should return to Capitol Hill armed not only with information about the situation in Syria but also with the sentiments of the people he represents.