April 22 (Bloomberg) -- Democrats Barack Obama and Hillary Clinton scrapped for last-minute advantage in today's Pennsylvania presidential primary with a flurry of campaign events and pitches to fans of news, comedy and wrestling.

The two candidates also engaged in a fresh round of sparring through television ads and interviews before the biggest contest left in the nomination race.

``I like to ask audiences to consider this as a hiring decision,'' Clinton said on MSNBC's ``Countdown with Keith Olbermann'' show. ``If you were to hire the person you thought was ready on Day One to do the toughest job in the world, what would you look for?''

Obama, campaigning in the suburbs of Philadelphia, also trained criticism on Arizona Senator John McCain, who has locked up the Republican nomination and was stumping in the South.

Both campaigns sought to damp expectations for today's vote. A Bloomberg/Los Angeles Times poll of likely Democratic voters published last week showed Clinton with a 46 percent to 41 percent edge in Pennsylvania. There are 158 pledged delegates at stake in the state, and Clinton is counting on a victory to keep her campaign going as she trails Obama in the number of delegates needed to win the nomination and in the total popular vote.

``We think there's going to be high turnout tomorrow,'' Obama, an Illinois senator, said during an appearance last night on ``The Daily Show'' on the Comedy Central cable channel. After Clinton started the campaign with a 20-point lead in Pennsylvania, ``the polls are now showing us about 6 to 8'' percentage points behind, he said.

Any Margin

Clinton campaign officials said Obama has outspent her by 3- to-1 and the New York senator said any margin of victory would be good enough.

``A win is a win,'' Clinton said on CNN's ``Larry King Live'' program last night. ``We're going to go all the way through this process and see where we stand in June.''

Illustrating the candidates' efforts to reach every possible voter, Obama, Clinton and McCain made taped appearances on World Wrestling Entertainment Inc. program ``Monday Night RAW'' on the cable channel USA Network.

The WWE says the weekly program draws 5 million viewers, and all three candidates used wrestling themes for their messages.

``Tonight, in honor of the WWE, you can call me Hillrod,'' Clinton, 60, said in her segment ``This election is starting to feel a lot like `King of the Ring.' The only difference? The last man standing may just be a woman.''

Wrestling for the Top

Obama, 46, noted that ``this is a historic time for America. It's not just that the reign of Randy Orton may soon be coming to an end.'' Orton is the reigning WWE champion.

In addition to Obama's appearance on Comedy Central and Clinton's on ``Larry King Live,'' both taped interviews with the three main broadcast networks. At almost every stop yesterday, they talked with local television and radio programs.

Extending their battle on the airwaves, Clinton released a 30-second advertisement in Pennsylvania that includes images of the Japanese attack on Pearl Harbor, Fidel Castro and Osama bin Laden.

``It's the toughest job in the world,'' the announcer says as the pictures flash by. It concludes by asking, ``Who do you think has what it takes?''

The ad is similar in theme to the ``3 a.m. phone call'' spot that her campaign advisers regarded as helping Clinton win the Texas primary.

Obama's Response

Obama campaign officials responded by accusing Clinton of using scare tactics and countering with an ad of their own.

``Who made the right judgment about opposing the war and had the courage and character to speak honestly about it? And who in times of challenge will unite us - not use fear and calculation to divide us?'' the announcer in Obama's ad asks.

Obama reinforced that response last night at a town-hall event in McKeesport.

``Let me ask you a question: there are three candidates left, who do you want answering that 3 a.m. phone call? The person who got Iraq wrong or the person who got Iraq right,'' Obama said.

Clinton used her CNN and MSNBC appearances to say she would consider a gas-tax holiday and making up revenue for the federal highway trust fund by taxing oil-company windfall profits.

Voter Registrations

Interest in the race is high in the state, judging by voter registrations. The Pennsylvania Department of State reported that 4.2 million people have registered to vote as Democrats for the primary, compared with the 3.7 million registered before the primary in 2004. Republican registration was 3.2 million, roughly the same as four years ago.

The next two states to hold primaries are Indiana and North Carolina, which vote on May 6. The North Carolina Democratic Party today said a proposed April 27 debate between Obama and Clinton was canceled because of ``time constraints and logistical issues.''

The party also noted in a statement on its Web site that the drawn-out race between the two Democrats may be taking a toll. ``There were also growing concerns about what another debate would do to party unity,'' the party said.

To contact the reporters on this story: Lorraine Woellert in Pittsburgh at lwoellert@bloomberg.net; Julianna Goldman in Blue Bell at Jgoldman6@bloomberg.net.

Last Updated: April 22, 2008 00:01 EDT