In Midwest, candidates trade barbs on politics, tone of race

John McCain in Hanoverton, Ohio: Barack Obama "began his campaign in the liberal left lane of politics and has never left it. He's more liberal than a senator who calls himself a socialist."

Barack Obama in Des Moines: "I will not take the low road to the highest office in this land. Those words were spoken eight years ago by my opponent, John McCain. But the high road didn't lead him to the White House then, so this time, he decided to take a different route."

McCain: "Obama praising McCain," 30 seconds.

Script: "The truth on global warming," the announcer says, before the ad cuts to Obama saying at a January 2007 Senate committee hearing, "The right approach begins with the proposal put forward by Senator Lieberman and Senator McCain. The Lieberman-McCain bill establishes limits for greenhouse gas emissions. It's a framework that's not only good for the environment, it's also good for business. I want to thank Senator Lieberman, as well as Senator McCain, for the outstanding leadership that they've shown."

The ad ends with images of wind turbines and the words on screen: "For a renewable energy and a brighter future, vote McCain."

Obama: No new national ad.

McCain: Rallies in Newport News and Springfield, Va., and Perkasie, Pa. Also appears on "Saturday Night Live."

Obama: Rallies in Henderson, Nev., Pueblo, Colo., and Springfield, Mo.

GLOBE STAFF AND ASSOCIATED PRESS