As concerns mount over the war in Iraq (search), long-shot presidential candidate Ralph Nader (search) sees an opening he didn't have a few months ago to be a larger player in the presidential race, say aides close to the consumer-rights advocate.

Nader is expected to increase his criticism of presumptive Democratic presidential nominee John Kerry (search) for his approach to Iraq, and argue there's not a dime's worth of difference between Kerry and President Bush (search).

"They're both in effect saying the U.S. stays the course ... that means indefinite occupation. That means more resistance, more insurgents, more guerrilla warfare, more kidnappings," Nader told Fox News.

Nader says Iraq needs fewer U.S. troops, must have a set date for withdrawal, internationally- supervised elections and its own path for reaching democracy.

Democratic operatives say Nader's positioning of himself as the anti-war candidate could cost Kerry votes. Kerry aides accuse Nader of pandering to the hard left and recklessly misreading the stakes in Iraq.

Click here to watch a report by Fox News' Major Garrett.