Our Washington bureau has already shown that, when it comes to talking about the veepstakes, Sen. Claire McCaskill has trouble staying mum.

But even when she doesn’t address it, her smile speaks for itself.

On CNN yesterday, Wolf Blitzer had McCaskill on, nominally to discuss the latest controversy surrounding Barack Obama’s vice-presidential search committee.

But then Blitzer, in front of a national cable audience, read McCaskill what Obama said about her in a story from our very own Jo Mannies:

I can tell you, there are very few people who are closer to me, who I have relied on more for counsel or advice. Should I be successful in this campaign, she will be somebody who has the utmost access to the Obama administration.

That sure sounds like somebody who is on the vice-presidential short list, Blitzer said to McCaskill.

“It’s an honor to be mentioned,” a glowing McCaskill replied. “I have complete trust in Senator Obama’s judgment in this regard. And I can’t wait to help President Obama swing some really strong punches for change…”

Pause.

“As a senator from Missouri,” McCaskill finished.

Though for anyone watching the segment — where’s YouTube when you need it? — McCaskill’s broad grin seemed to speak louder than her words.