CNN's Brianna Keilar reports.
Aides to the Commander-in-Chief say President Obama didn't tell anyone about his plan to ask Congress for permission to proceed with military strikes in Syria until Friday at 6pm, when he took a 45-minute walk with Chief of Staff Denis McDonough.
Shortly after, at 7 p.m, the President tells his National Security staff of the decision, sparking a heated debate.
Saturday morning, he calls his top team to the Situation Room to finalize the plan, then calls Congressional leaders from the Oval Office and heads to make the announcement to the public.
Speaking from the Rose Garden,the President says "All of us should be accountable as we move forward and that can only be accomplished with a vote."
Secretary of State Kerry also recently revealed new evidence to back claims the Assad regime killed hundreds of his people with nerve gas.
"Blood and hair samples that have come to us has tested positive for signatures of Sarin," Kerry said.
Despite this evidence, CNN's Chief Congressional Correspondent Dana Bash says the President has his work cut out for him as support for military action abroad is far from guaranteed.
Bash reports that lawmakers emerged from a classified briefing Sunday intended to convince them to authorize force in Syria seemingly unconvinced, despite reports the administration appealed to their sense of patriotism and morality.
Texas Rep. Michael Burgess said, "The mood in the district I represent is, do not do this. And I honestly did not hear anything that told me I ought to have a different position."
The resistance to action cuts across the aisle.
Connecticut Democrat Jim Hines adds, "I'm still very skeptical about the President's proposal. It's not clear to me that we know what the results of this attack would be, meaning it would be effective."
Concern also lingers over authorizing a bill many lawmakers currently find too broad for the limited action that has been publicized.
Republican Senator Roy Blunt, Missouri, says "The biggest single concern among members may very well have been a very broad request for authority with a supposedly very narrow intent to do anything."
The administration continues to meet with key figures and later Monday, Senators' John McCain and Lindsey Graham are expected to go to the White House to meet with the President.