John Kasich

Nine months after Donald Trump became a presidential candidate, his rivals are still searching for a formula to stop his improbable political rise.

Anxious Republican officials are coming to terms with the idea that their second least favorite GOP presidential candidate — polarizing Texas conservative Ted Cruz — may be the party's best last chance to stop Donald Trump.

Should he succeed, Kasich would deprive Donald Trump of the 66 winner-take-all delegates, slowing the businessman's path toward clinching the GOP nomination outright.

Bernie Sanders breathed new life into his longshot White House bid with a crucial win in Michigan's primary Tuesday night, chipping away at Hillary Clinton's dominance in the Democratic presidential race. Republican Donald Trump swept to victory in Michigan, Mississippi and Hawaii, overcoming fierce efforts to blunt his momentum.

In a split decision, Ted Cruz and Donald Trump each captured two victories in Saturday's four-state round of voting, fresh evidence that there's no quick end in sight to the fractious GOP race for president. On the Democratic side, Bernie Sanders notched wins in Nebraska and Kansas, while front-runner Hillary Clinton snagged Louisiana, another divided verdict from the American people.

Five more states are chipping in verdicts on the Republican and Democratic presidential contests in races largely overshadowed by Super Tuesday and the big contests still to come.

Front-runner Donald Trump delivered a broadside against competitor Ted Cruz, telling thousands in Las Vegas he thinks the Texas senator "is sick."

When the calendar turns to March in this year of the irate voter, the first wave of congressional Republicans will find out whether they have their very own Dave Brat waiting for them.

Jeb Bush, John Kasich and Marco Rubio are locked in a high-stakes political chess match in South Carolina, strategically moving money and other campaign resources around in a bid to pull ahead in the Republican primary race -- or at least keep their campaigns afloat if they don't.

The unexpected death of Supreme Court Justice Antonin Scalia -- and the immediate declaration from Republicans that the next president should nominate his replacement -- adds even more weight to the decision voters will make in November's general election.