Is Vice President Biden teasing a 2016 run?

A source close to Hillary Clinton has told CBS News that the former Secretary of State is considering speaking out about the private email controversy. Her silence is generating noise about other options for Democrats in 2016, including Vice President Joe Biden, reports chief White House correspondent Major Garrett.

In February, Biden visited Iowa, the state that hosts the first presidential caucus. He also visited South Carolina and New Hampshire, the two most important early primary states. Among national Democrats, Biden is the only one to visit all three this year.

"We are still the largest value-added manufacturer in the world," Biden said in South Carolina.

With Hillary still on the sidelines, Biden's schedule suggests he's keeping his options open.

"Timing is everything in this life," said New Hampshire Sen. Lou D'Allesandro, who has backed Biden for years.

"We know there comes a time when there's an opening, if that opening is something you believe strongly in, you make a move," D'Allesandro said.

Biden has strengths: He's President Obama's point-man on Ukraine, Iraq, Afghanistan, Central America and South America, he managed stimulus spending without controversy and cut deals with Republicans to avert a government shutdown and default.

"I've got somebody who I think will go down as one of the finest vice presidents in history, and he has been, as I said earlier, a great partner in everything that I do," Mr. Obama said to CBS News in April.

That hasn't changed, but neither has Biden's ability -- seemingly endless ability -- to act and speak, memorably.

The infamous "Bidenisms" include everything from an odd moment with Defense Secretary Ash Carter's wife at his swearing in, to a faux-pas at the Health Care Bill signing ceremony where Biden not-so-quietly whispered to Obama, "This is a big f---ing deal."

He turned heads talking foreign policy strength in 2012, telling the crowd, "I promise you, the president has a big stick. I promise you."

His welcoming message to a new senator in 2013 didn't go unnoticed either: "Spread your legs, you're going to be frisked."

Biden supporters in New Hampshire and South Carolina said they feel they're being teased -- that even in confidential conversation, Biden refuses to give them a straight answer.

Those close to the vice president describe him as a cold-eyed realist working through a process, but it is important also to note that, up until today, Biden has hired no one, organized nothing, and raised no money for any potential 2016 bid.