Cruz's recent gains mark the first time since November that one of Trump's rivals has threatened his lead.
From abortion to NATO, Trump hit on hot-button issues two days before the Wisconsin primary.
Being Republican has long meant being like Reagan—or at least saying you're like Reagan.
Donald Trump and John Kasich participated in town halls for a second consecutive night.
The three Republicans hinted at no longer pledging to support their party's eventual nominee.
Donald Trump, Ted Cruz and John Kasich participated in a town hall on Tuesday night in Milwaukee.
The Wisconsin governor announced his decision a week before his state's primary.
In a speech in Wisconsin, Clinton put the future of the court at the center of the election debate.
The Wisconsin primary kicks off April's nominating contests.
"I do not make a habit out of supporting people who attack my wife and attack my family," Cruz said in an interview.
On Tuesday night, the GOP front-runner threatened to "spill the beans" on Ted Cruz's wife.
Arizona is the biggest prize for both parties Tuesday night.
Residents in three Western states are casting their picks as national security once again is a hot-button issue.
Twin explosions in Brussels will test how the contenders would protect the U.S. as president.