CBS/AP) CBS News projects that Democratic Illinois Sen. Barack Obama will win in Vermont, securing the first win tonight among four states holding primaries.
In the crucial state of Ohio, where polls closed at 7:30 p.m. ET, Obama and Hillary Rodham Clinton are battling it out.
Sen. John McCain will win the Republican primaries in Ohio and Vermont, CBS News also projects.
Obama and Clinton also contested primaries in Texas and Rhode Island on Tuesday, the front-runner and his pursuer in a riveting race for the Democratic presidential nomination.
Republicans also vote in the four states Tuesday. McCain reached out for the Republican delegates needed to secure his nomination after a decade's struggle.
In all there were 370 Democratic delegates at stake in Rhode Island, Vermont, Ohio and Texas, which uses an unusual primary-caucus system.