WATERLOO - Hillary Clinton and Barack Obama continued a political boxing match on Monday after Clinton, in a thinly veiled swipe at Obama, criticized her rivals for inexperience.

At the same time, in an interview with The Courier during a campaign stop at the Dr. Walter Cunningham School for Excellence in Waterloo, Clinton denied a report by conservative columnist Robert Novak that her campaign reported having scandalous information on Obama.

Clinton said in Knoxville that the country can't afford "on-the-job training" in the White House.

The Obama campaign, as it has all weekend, pushed back forcefully against criticism of the Illinois senator. Obama spokesman Tommy Vietor pointed to a new ABC News/Washington Post poll that showed Obama may hold a slight lead in Iowa a little more than six weeks before the caucuses.

"Having lived by the polls, Hillary Clinton is now panicked by them," Vietor said. "It's not a surprise that on the day a poll comes out that shows Sen. Clinton is behind, she starts lobbing these criticisms at him."

The poll shows 30 percent of Iowans support Obama, with 26 percent favoring Clinton and 22 percent for Edwards. The numbers have changed little - all within the margin of error - since a July ABC News/Washington Post poll showed the race in a dead heat.

It also found 38 percent of Iowans believe Clinton has the "best experience" for president, down significantly from 50 percent in July. Only 11 percent believe Obama has the "best experience."

The Clinton camp said the new poll only shows the race is too close to call. Mo Elleithee, a Clinton spokesman, said Iowa will see "a lot of Sen. Clinton and the former president (Bill Clinton)" in the coming weeks.

"It's going to be tight race down to the wire," he said.

Acrimony between the campaigns started this weekend after conservative columnist Novak wrote the Clinton campaign had been whispering it had scandalous information on Obama, but decided against using it.

Novak stood by his comments today, and added Clinton's actions reminded him of former President Richard Nixon's tactics. Clinton served on the staff of the House Judiciary Committee when it drafted impeachment articles against Nixon in 1974, after which he resigned from office.

In the Courier interview, Clinton again denied her campaign ever suggested it had scandalous information on Obama.

"It's totally untrue, and I don't understand what motivates him," she said of Novak. "He's not a friend to Democrats, that's very clear."

When asked about her reaction to Obama's response to the column - her campaign has criticized Obama for playing into Republican hands - she said:

"You'll have to ask them why they do what they do, and why they say what they say."

Obama responded aggressively to the Novak column this weekend, demanding Clinton reveal any information or deny the claim.

Contact Jens Manuel Krogstad at (319) 291-1580 or jens.krogstad@wcfcourier.com.