Today in Politics: A Continuing Biden Watch, With Several False Alarms

Good Tuesday morning. With the campaign trail mostly quiet, eyes turn to Congress, which is hitting the ground at a clip in its return from recess. But when word came, again, on Monday that the Democratic field was about to grow by one very big name, the frenzy grew and echoed until, again, it died down, and decisions were said to be maybe a few days away after all. Again.

One thing is for certain: Vice President Joseph R. Biden Jr. may definitely be running for president, or not, by the time this week is over.

Biden Watch has entered its 12th week, and fever-pitch speculation has accompanied it. So have the whisper-down-the-lane reports about his impending announcement, or lack thereof.

A Fox News report on Monday morning that Mr. Biden was going to run had a viral effect on Twitter that lasted about two hours — until it was discounted. Rumors that Mr. Biden would make his intentions known within 48 hours — meaning ahead of Hillary Rodham Clinton’s testimony before a House committee investigating the 2012 attacks in Benghazi, Libya — appeared to be exaggerated.

Still, the realities of the calendar loom. They include the Iowa Democratic Party’s Jefferson-Jackson Dinner on Saturday evening, where the declared candidates are scheduled to speak. Mr. Biden spoke at the dinner in 2007, when he was seeking the nomination against Mrs. Clinton and Barack Obama. His speech barely registered.

The event is also noteworthy for how campaigns road-test their organizational muscle by pulling out supporters. Senator Bernie Sanders of Vermont, who has an ardent fan base, is certain to get his supporters out. Mrs. Clinton had already planned to have the singer Katy Perry headline a pre-dinner rally.

But Mrs. Clinton appears to be taking few chances with the threat of Mr. Biden: Her husband, the former President Bill Clinton, who is a known draw for crowds, will make his first rally appearance in Iowa this season before the dinner.

The backdrop to it all is Mrs. Clinton’s testimony before Congress on Thursday, which her campaign hopes will be another turning point in her favor, after several difficult months.

As for Mr. Biden, he sounded an emotional note at an event honoring the U.S.O. at his official residence on Monday evening.

Regarding the group’s aid to troops returning from battle, Mr. Biden said, “My dad used to say, ‘get back up when you get knocked down.’ ”

He added, “Well, it makes a difference when someone is reaching down to help you up.”