Sen. Barack Obama, D-Ill., and his team may have passed their first real presidential test -- they can keep a secret.
Obama and his White House rival Sen. John McCain, R-Ariz., are both enjoying the anticipation of their looming choices for vice presidential running mates.
McCain's camp has indicated that he is still mulling his choices, but Obama has a real secret to keep.
The presumptive Democratic nominee has made his choice, but as of Monday night he hadn't even shared that information with the person he selected.
And it's not clear whether the winner of the Democratic veepstakes has yet to be notified.
Intent on finding clues, veep watchers have staked out the homes of those believed to be on Obama's short list and are monitoring every word, schedule and grooming change.
One possible slip may be an indication that Obama has finally ruled out New York's Sen. Hillary Clinton and two-term Kansas Gov. Kathleen Sebelius.
Obama usually uses the phrase "he or she" when talking about a future running mate, but in a speech in Raleigh, N.C., Tuesday night, he dropped the "she."
"My vice president also, by the way, will be a member of the executive branch. He won't be one of these fourth branches of government where he thinks he's above the law," Obama said.
Other clues are more circumstantial.
Obama will be campaigning in Virginia Thursday with Gov. Tim Kaine, one of three believed to still be on Obama's list.
It's expected Obama will make his vice presidential announcement public by the end of this week if for no other reason that simple necessity: the Democrats' nominating convention opens in Denver Monday.
Unless Kaine's grin was a hint, the governor gave no clue if has finally been told by Obama that he is -- or isn't -- the one.
"I won't talk about my conversations, but we're thrilled he'll be in Virginia," Kaine said Tuesday.
Nothing is beyond scrutiny as the summer heat sizzles and political reporters angle to break one of the few anticipated big moments in a presidential campaign.
When Susan Bayh, wife of Indiana Sen. Evan Bayh, got her hair and nails done this week and told neighbors that she had to "prepare for a media pack," was it another clue or just coincidence?
Sen. Joe Biden, D-Del., may have given up something Tuesday when he told reporters while driving slowly past them, "It isn't me," but since then he's refused to elaborate.
This morning he cruised past the press pack at the end of his driveway with his windows rolled up.
He returned a short time later and rolled his window down long enough to hand over a brew box of coffee and a dozen bagels. "Nice talking to you," was all he said.
The only people who know for sure who the choice is could fit into a midsize car.
Besides Obama, there are two people who led the vetting process, Caroline Kennedy and former Justice Department official Eric Holder; top campaign aides David Axelrod and David Plouffe, and Obama's wife Michelle were also involved.
Mike Feldman, former top aide to one time Democratic presidential candidate Al Gore, said there is a good reason for Obama to protect his secret.
"They have very few moments where they can completely control: the nomination and announcing -- this is one of those," Feldman said.