At 6 p.m., he spoke via secure video teleconference with U.S. commander Gen. Stanley McChrystal, who asked for at least 40,000 more troops, and ambassador to Afghanistan Karl Eikenberry, who warned the president in classified cables of his concerns about sending more troops with Karzai in power.
"Both of those individuals felt very good about our way forward," Gibbs said.
The president spent much of today consulting key U.S. allies -- the heads of Denmark, France, Russia and the U.K., and the prime minister of Australia, who sent more troops to Afghanistan earlier this year.
"Australian takes its alliance with the United States very seriously. That's why we have been with America for a long time in Afghanistan and why we will be with America for the long haul," Australian Prime Minister Kevin Rudd said.
The president will call Afghan President Hamid Karzai and Pakistan President Asif Ali Zardari tonight or Tuesday before his speech.
Today's calls to foreign leaders were to update them on the "strategy, the process that's gone into this," Gibbs said. Clinton will head to Europe for meetings with NATO next week, where she will present the Obama administration's plan in person and make the case for NATO contributions.
Clinton and Obama have both reached out to their allies and would like to see NATO contribute 5,000 to 10,000 troops to Afghanistan.
Obama is putting the finishing touches on his speech Tuesday night, which will be broadcast at 8 p.m. ET from the U.S. Military Academy at West Point, N.Y. Obama is expected to call for an additional 30,000 troops for Afghanistan at an estimated cost of $1 million per soldier.
"The president will talk about, this not being 'an open ended commitment,' that the goal and the purpose of the strategy is to train an Afghan national security force, comprised of an Afghan national army and a police that can fight an unpopular insurgency in Afghanistan so that we can then transfer that security responsibility appropriately back to the Afghans," Gibbs said. "I think he will go through why we are there, what he believes of this process, what this process brought about and outline what he hopes to see."
The decision comes after months of discussions and deliberations with the president's national security team. McChrystal had requested 40,000 additional troops for Afghanistan, but Eikenberry and several Democratic lawmakers opposed the move, saying that Afghanistan's government needs to reduce corruption.
Before leaving to give his speech at West Point, the president will meet with congressional leaders at the White House to explain his decision.
And on Wednesday morning at 9 a.m., the Senate Armed Services Committee has scheduled a public hearing on Afghanistanin which Clinton, Gates and Chairman of the Joint Chiefs of Staff Adm. Michael Mullen will testify.
Sources say the president's speech will touch on four major points.