Deputy national security adviser Tony Blinken built his reputation in Washington by being the smartest — and most soft-spoken — aide in the room.

But now the former adviser for Vice President Joe Biden has been thrust into the spotlight as the point man for the Obama administration’s contentious push to win congressional authorization for a military strike on Syria.

Blinken has long been a central player in the White House. He was in the Situation Room when President Obama's inner circle learned that Navy SEALs had killed al Qaeda leader Osama bin Laden.

In the famous photo capturing the tense moments during the raid on bin Laden's compound, Blinken seemingly fades into the background, looking over the shoulder of then-White House Chief of Staff Bill Daley.

Blinken, though, is now front and center and the stakes couldn’t be much higher.

His newfound role was accelerated when National Security Adviser Susan Rice joined Obama for his trip to the G-20 summit in St. Petersburg, Russia, leaving Blinken, the understudy, as the public face of the administration's push in Washington.

The foreign policy wonk took on the task and is seemingly everywhere these days, selling a Syria strike to a war-weary public and lawmakers suspicious of another military engagement in the Mideast.

It was Blinken who joined White House press secretary Jay Carney in the briefing room Monday to detail the outreach to Capitol Hill. Blinken was also repeatedly deployed to serve as the administration's voice on cable television. And it was Blinken, along with Biden, who briefed lawmakers in classified meetings from the Situation Room.

If Obama doesn't win congressional support for use of force in Syria, his leverage on an array of second-term and legacy-defining issues could be significantly weakened.

So why is Blinken, a relative unknown, who once jokingly referred to himself as “Allen and Rossi” — the comedy duo that followed the Beatles on “The Ed Sullivan Show” — in such an important role?

“Tony is going to be a very serious player for a long time,” said former Sen. Ted Kaufman, D-Del., Biden's longtime Senate chief of staff, who succeeded him briefly in the upper chamber. “The president has felt this way about him for a while. Early on, he was inviting Tony into meetings where Tony would be the most junior person in the room. I knew this would happen eventually — this is Tony's moment.”

One former high-level administration official had a simple explanation for Blinken's rise from anonymous staffer to high-profile surrogate.

“Blinken knows his stuff,” the former national security official said.

A graduate of Harvard University and Columbia Law School, Blinken, 51, served as a National Security Council staffer for seven years, a senior fellow at the Center for Strategic and International Studies and then staff director of the Senate Foreign Relations Committee under Biden.

Blinken was not available for an interview with the Washington Examiner.

After a stint as the vice president's foreign policy adviser, Obama promoted Blinken to deputy national security adviser in January, giving him greater control over the response to Syria’s civil war.

Blinken's name was also floated for Obama's next national security adviser before the post went to Rice, the former United Nations ambassador.

Still, his clout in Washington is on the rise.

White House officials say that a favorite phrase of Blinken's is “superpowers don't bluff.”

It's a sentiment that clearly stuck with Obama as he looks to follow through on his “red line.”

Blinken’s ascension from behind-the-scenes policy adviser to a public power player, however, hasn't been flawless.

Last week, Blinken said Obama had no “intention” to strike Syria without congressional backing. The president was forced to walk back the comments, not wanting to telegraph his blueprint to lawmakers weighing a tough vote.

Unable to ignore the gaffe, Blinken this week simply said he “didn't speak very artfully” and that he wasn't “going to jump ahead” of the president.

“Welcome to the big leagues,” quipped one senior GOP Senate aide, who said that despite the high-profile mistake, he's been “impressed with how Blinken carries himself.”

“He doesn't have an easy job,” the Senate source said. “He's selling a product that most Americans have no interest in buying. But he's still quite convincing.”

If Blinken has one goal in the Syria debate consuming Washington, it's to convince Congress and the public that not punishing Assad would have cataclysmic results, effectively inviting Iran and other dictatorial regimes to challenge the U.S.

“Are we or are we not going to do anything about the fact that Assad poisoned his own people with gas, including hundreds of children?” Blinken asked, facing the cameras, under the glaring lights in the White House briefing room Monday.

He predicted that when lawmakers “see the facts, I think they’ll come to the right conclusion.”