PENNSYLVANIA

Mitt Romney's failure to secure a decisive victory on Super Tuesday underscores lingering questions about his candidacy and almost guarantees the Republican presidential nomination will stretch on.

Capping victories in five other states Tuesday, Mitt Romney won Ohio's Republican primary, narrowly beating Rick Santorum. But with the win come questions about Romney's campaign strategy and the candidate's appeal.

Republican presidential frontrunner takes five out of 10 states but Rick Santorum stays in the running.

Rick Santorum has been projected winner of the Oklahoma primary.

He and Ron Paul were the only ones on the ballot.

Where to watch Tennessee primary results.

Vermont is one of 10 states that will be holding its Republican presidential contest Tuesday night on one of the most important and revealing evenings of the 2012 GOP nomination process.

Virginia is one of 10 states that will be holding its Republican presidential contest Tuesday night on one of the most important and revealing evenings of the primary.

The progressive icon from Ohio could lose his long-held congressional seat to fellow Ohio incumbent Marcy Kaptur in a Democratic primary that is among Super Tuesday's slate of contests.

Mitt Romney can take a big step toward finishing off chief rival Rick Santorum and seizing command of the Republican presidential race Tuesday as 10 states hold contests with Ohio at ground zero.

Fallout over Rush Limbaugh calling Georgetown Law School student Sandra Fluke a slut and a prostitute is now hurting the conservative radio show host among his core audience, according to a new poll released today.

Operation Hilarity, which encouraged Democrats to vote for Rick Santorum, the forum Pennsylvania senator, in last week's Michigan primary, is the brainchild of the popular left-wing blog Daily Kos.

Many counties have stopped adding fluoride to their water supply, citing health risks the CDC says simply aren't there.

Getting the government out of education has become a recurring theme during the 2012 Republican presidential primary, and Rick Santorum has embraced it by emphasizing his decision to home school his children.

Mitt Romney closed in on Rick Santorum in Ohio and picked up a crucial endorsement in Virginia on Sunday as he grows in strength ahead of Super Tuesday, the biggest day yet in the race for the 2012 Republican presidential nomination.

Former Massachusetts governor Mitt Romney is tied with former senator from Pennsylvania Rick Santorum in Ohio Republican primary, according to a poll released by Reuters/Ipsos Sunday.

With Mitt Romney springing ahead and Rick Santorum falling behind, the Republican Party's presidential primary election in Ohio is looking like a dead heat, setting the stage for a cliffhanger of a contest on Super Tuesday this week, according to a Reuters/Ipsos poll released Sunday.

It's one of the biggest nights of the election year, and for the GOP presidential nomination contest, it could be a game-changer. Although the GOP primaries and caucuses began two months ago on Jan. 3 in Iowa, in recent weeks, everything has been building up to Super Tuesday.

Santorum, the former Pennsylvania senator, pulled in 35 percent of those polled by Quinnipiac University, while Romney, the ex-Massachusetts governor, received 31 percent.

The Senate narrowly backed a key plank of President Barack Obama's healthcare reform Thursday by rejecting a sweeping Republican measure that would have allowed employers to opt out of birth control coverage and other medical services on moral grounds.

Latinos, a large and growing voting bloc in several swing states, could play a pivotal role in deciding the U.S. presidential election. A raft of tough new state immigration laws, combined with rhetoric from its candidates, could hurt the Republican Party in November.