Secretary of State John Kerry and Secretary of Defense Chuck Hagel will testify before the Senate's Foreign Relations Committee Tuesday afternoon, an initial step to convince members to intercede in Syria.
It will be the first public opportunity lawmakers have had to debate whether the U.S. government should take action against the Syrian government for its alleged use of chemical weapons against its own people.
The last-minute interruption to the August recess comes after President Barack Obama announced over the weekend he would leave the final decision to strike Syria up to Congress, a move many lawmakers applauded.
"The president is right to seek the support and approval of the United States Congress before moving forward with military action," Sen. Angus King, I-Maine, said.
A small minority criticized the president for abdicating his role as commander in chief.
"The president does not need Congress to authorize a strike on Syria," Rep. Peter King, R-N.Y., said. "The president doesn't need 535 members of Congress to enforce his own red line."
Tuesday's hearing represents a larger public relations campaign to drum up public support to intervene in the region after Syrian President Bashar al-Assad was found to have unleashed chemical weapons on civilians, killing more than 1,400. The administration has called it the worst chemical weapons attack in 25 years.
But finding broad support won't be easy.
Already, the Obama administration has had to work overtime to convince key Democrats that the intervention will be "limited" in scope and will not entangle the U.S. in another overseas conflict for years to come. Kerry attempted to quell concerns Monday in a conference call with more than 100 Democrats, but some were still not convinced.
Issuing a statement after the call, Rep. Rick Nolan, D-Minn., was skeptical the administration had enough proof that Assad's regime had even used Sarin gas on civilians despite Kerry citing forensic evidence inspectors found at the scene of the crime.
The Obama administration seemed to be having more luck with Republicans Monday.
Obama invited defense hawks Sens. Lindsey Graham, R-S.C., and John McCain, R-Ariz., to the White House to discuss what kind of approach could attract a broad coalition of congressional support. Graham and McCain have long advocated for a more aggressive intervention that could "degrade Assad's capabilities."
The GOP lawmakers, leaving the meeting, warned that there was a long road ahead to convince a majority of their colleagues that a strike against Syria is necessary.
McCain said if Congress cannot come to a consensus, the results "would be catastrophic."
The moment of truth will come Sept. 9, when members of Congress vote on a resolution to attack Syria.
Kerry predicted once the administration finished testifying in front of the House and Senate foreign affairs committees and meeting one-on-one with lawmakers this week, Obama would have the votes.
"I can't contemplate that Congress would turn its back on all of that responsibility," Kerry said during an appearance on "Fox News Sunday."
- Kerry Makes Case for Military Strike in Syria
- Chuck Hagel on Syria: U.S. Ready to Go
- Opinion: Why the U.S. Should Not Intervene in Syria
Corrected 9/3/13: A previous version of this article included an incorrect political affiliation for Rep. Angus King.