EVANSVILLE, Ind. — Sen. Hillary Clinton and Sen. Barack Obama crisscrossed two states yesterday, waging a last-ditch push for votes in Indiana and North Carolina even as both vowed to keep campaigning through the month regardless of today's results.

"This is gonna be a tight election here in Indiana. Every poll shows a dead heat," Obama told union members at an early morning event in Evansville before jetting off to North Carolina.

"We need every single vote."

Clinton launched a new TV ad, pitching her proposal to suspend the federal gasoline tax and ripping Obama for opposing it.

"He is attacking Hillary's plan to give you a break on gas prices because he doesn't have one," the ad said.

Indiana is shaping up as the key battleground, where a Clinton victory in Obama's backyard would be her first in a state bordering the Illinois senator's home and perhaps would reinforce the weakness he has shown in recent contests, where he has lost working-class whites decisively. Clinton led there by 5.3 percentage points in an averaging of recent polls cited by RealClear

Politics.com.

An Obama win in Indiana, however, could signal that he has regained his front-runner footing after a firestorm of criticism over his former pastor and his comment about working-class voters clinging to God and guns out of bitterness.

The contest doesn't appear to be as close in North Carolina, where Obama leads by 7 percentage points in an averaging of recent polls cited by Real

ClearPolitics.com.

One prominent and neutral Democrat, former Rep. Harold Ford of Tennessee, said yesterday that Clinton appeared to be gaining in both states, thanks to her detailed promise to help working-class voters worried about pocketbook issues, particularly her proposal to suspend the federal gas tax.

While a split decision — such as Clinton winning Indiana and Obama winning North Carolina — could leave the contest unchanged, either candidate could change the dynamic of the race heading into the final weeks by winning both today.

"If he wins both, it's over for her," Ford said. "If she wins both, I don't know how it doesn't move it to her favor."

Meanwhile, in Charlotte, presumptive GOP nominee John McCain defended his support for a gas-tax holiday, current U.S. policy in Iraq and a tough line against Iran.

McCain, 71, cast November's choice in stark terms.

"Do you want the government to run healthcare or do you want families to run healthcare?" he said, referring to both Democrats' plans to mandate insurance for at least some Americans. McCain would make it "affordable and available," but not mandatory.

He also said either Democrat would "surrender" in Iraq, a situation he said would lead to "chaos and genocide." Both Democrats favor the staged withdrawal of U.S. troops.