Claws come out, as Sanders closes in on Clinton

WASHINGTON D.C. -- On the Democratic side, it can't get much tighter than this.

The latest poll in Iowa shows Hillary Clinton just two points ahead of Bernie Sanders -- and that is within margin of error, virtually a tie.

"I have felt for the last several weeks that we had the wind at our back," Bernie Sanders previously said.

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Sanders' feelings were confirmed on Thursday. And the latest poll brought back vivid memories of 2008 when Clinton's commanding lead in Iowa slipped away at the end.

Then and now, her powerful campaign and its war chest were supposed to overpower insurgent opponents. But it is Sanders who is holding down larger rallies while Clinton sticks to town halls.

Sanders is also airing more television ads reaching voters like Tim Pool of Topeka, Iowa.

"I totally agree with Senator Sanders, you can't have 2 percent of the people in this country making 400 times more than everybody else," said Pool.

On Thursday, Sanders surprised Clinton with a television ad that seemed to be aimed at her.

"There are two Democratic visions for regulating Wall Street," he said in the advertisement. "One says it's okay to take millions from big banks and then tell them what to do."

Bernie Sanders, left, offers an apology to Hillary Clinton during a Democratic presidential primary debate Saturday, Dec. 19, 2015, at Saint Anselm College in Manchester, N.H. Jim Cole, AP

The Clinton campaign accused him of violating a longtime promise.

"You're looking at someone who has never run a negative TV ad in his life, and never will," Sanders had previously said.

Clinton Campaign Manager Robby Mook convened a conference call with reporters to drive the point home.

"They made a repeated pledge to their supporters and donors and they're clearly backing off on that," he said.

But even that was reminiscent of 2008, when Clinton routinely tried to convince voters Barack Obama was just another politician, not a visionary. She can take heart that she is still leading by ten points among those who say they will definitely caucus on February 1.

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    Nancy Cordes is CBS News' congressional correspondent.