Mindful of public opinion, Kerry urged Americans to read the four-page assessment for themselves. He referred to Iraq — when Bush administration assurances that weapons of mass destruction were present proved false, and a U.S. invasion led to a long, deadly war. Kerry said this time it will be different.
"We will not repeat that moment," he said.
Citing an imperative to act, the nation's top diplomat said "it is directly related to our credibility and whether countries still believe the United States when it says something. They are watching to see if Syria can get away with it because then maybe they, too, can put the world at greater risk."
The president said firmly that the attack "threatens our national security interest by violating well-established international norms."
While Obama was having trouble enlisting foreign support, French President Francois Hollande was an exception. The two men spoke by phone, then Hollande issued a statement saying they had "agreed that the international community cannot tolerate the use of chemical weapons, that it must hold the Syrian regime responsible and send a strong message to denounce the use of (such) arms."
The day's events produced sharply differing responses from members of Congress — and that was just the Republicans.
Sens. John McCain of Arizona and Lindsey Graham of South Carolina said Obama needed to go further than he seems planning. "The goal of military action should be to shift the balance of power on the battlefield against Assad and his forces," they said in a statement.
But a spokesman for House Speaker John Boehner, Brendan Buck, said if the president believes in a military response to Syria, "it is his responsibility to explain to Congress and the American people the objectives, strategy, and legal basis for any potential action."
The looming confrontation is the latest outgrowth of a civil war in which Assad has tenaciously — and brutally — clung to power. An estimated 100,000 civilians have been killed in more than two years, many of them from attacks by the Syrian government on its own citizens.
Obama has long been wary of U.S. military involvement in the struggle, as he has been with turbulent events elsewhere during the so-called Arab Spring. In this case, reluctance stems in part from recognition that while Assad has ties to Iran and the Lebanese militant group Hezbollah, the rebels seeking to topple him have connections with al-Qaida terrorist groups.
Still, Obama declared more than a year ago that the use of chemical weapons would amount to a "red line" that Assad should not cross. And Obama approved the shipment of small weapons and ammunition to the Syrian rebels after an earlier reported chemical weapons attack, although there is little sign that the equipment has arrived.
With memories of the long Iraq war still fresh, the political crosscurrents have been intense both domestically and overseas.
Dozens of lawmakers, most of them Republican, have signed a letter saying Obama should not take military action without congressional approval, and top leaders of both political parties are urging the president to consult more closely with Congress before giving an order to launch hostilities.
Despite the urgings, there has been little or no discussion about calling Congress back into session to debate the issue. Lawmakers have been on a summer break for nearly a month, and are not due to return to the Capitol until Sept. 9. Obama has not sought a vote of congressional approval for any military action. Neither Republican nor Democratic congressional leaders have challenged his authority to act or sought to have lawmakers called into session before he does.
Senior White House, State Department, Pentagon and intelligence officials met for an hour and half Friday with more than a dozen senators who serve on the Foreign Relations and Armed Services committees, said Sen. Chris Coons, D-Del. He described the discussion as "open and constructive."
The White House will brief Republican senators in a conference call Saturday at the request of Senate GOP leader Mitch McConnell, R-Ky., a spokesman for the senator, Don Stewart, said.
Obama's efforts to put together an international coalition to support military action have been more down than up.
Hollande has endorsed punitive strikes, and told the newspaper Le Monde that the "chemical massacre of Damascus cannot and must not remain unpunished."
But British Prime Minister David Cameron's attempt to win a vote of approval in Parliament for military action ended in ignominious defeat on Thursday. American attempts to secure backing at the United Nations have been blocked by Russia, long an ally of Syria.
U.N. Secretary-General Ban Ki-moon has urged a delay in any military action until the inspectors can present their findings to U.N. member states and the Security Council.
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