But the bellwether state of Ohio has now rung, and no one can miss its message.

FORBES: After Super Tuesday, Romney Must Prove He Can Carry Conservative Banner

Inside the bellwether state is the bellwether town of Chillicothe, a town that often mirrors the state's election results.

CNN: Voters divided in Ohio's bellwether town

Obama also counted Missouri, a national bellwether state, among his victories, and the Illinois Democrat has been on a fundraising tear.

CNN: Analysis: McCain clear leader; split decision may help Obama

Ohio was important because no Republican nominee has taken the White House without winning the Midwestern bellwether state in the general election.

BBC: Super Tuesday: Romney edges out Santorum Ohio

Always a political bellwether state, Oregon has moved inexorably left, increasingly dominated by both its public sector and the particularly strong green movement.

FORBES: Magazine Article

Democrats are struggling in the bellwether state of Ohio, and may lose the tight Senate races not only in West Virginia but also in Pennsylvania and Wisconsin.

ECONOMIST: Lexington

Even before the 2000 Presidential election and the highly contested result there, Florida has been a bellwether state that shows where the nation as a whole stands politically.

FORBES: 3-Way Race Just Fine for Rubio

Governors, Super PACs, 527 independent expenditure committees, and the candidates themselves are raining down dollars on many Ohio counties this week on the perennial quest to win the bellwether state.

FORBES: Why Swing State Voters From Ohio Are Easier To Find -- In Florida

"Everyone is starting to believe Romney is the person who can beat the president and go on to turn the economy around, " said state Rep. Will Weatherford, a Republican and Romney supporter who represents the bellwether of Pasco County, just north of Tampa.

WSJ: Romney Wins Big in Florida Primary