Cruz said his amendment to the Senate immigration bill would help prevent "voter fraud."

Newark Mayor Cory Booker has led Rep. Frank Pallone Jr. in every poll of the Democratic Senate field by double-digit margins. 

The 7-2 vote split conservatives on the Supreme Court; Justice Scalia wrote majority opinion.

Sen. Mark Begich (D-Alaska) on Monday said he's closer to being a Rockefeller Republican than a Pelosi Democrat.

"Probably a Rockefeller Republican," the Alaska senator told CNBC Monday morning when asked whether he was closer to identifying as that or as a Pelosi Democrat.

The comment signifies Begich's efforts to put some distance between himself and national Democrats in the libertarian-leaning state.

The National Republican Senatorial Committee (NRSC) is pushing vulnerable Senate Democrats to say whether they trust the Internal Revenue Service to handle the implementation of ObamaCare.

The group issued releases Monday targeting four vulnerable senators — as well as three likely Democratic senatorial nominees — asking whether they agree with President Obama that the IRS can handle the launch of the complicated healthcare reform program. The IRS is not the primary government agency responsible for implementing the Affordable Care Act, but does have a role in the program.

The group, and other Republicans, have focused on the scandal over the IRS's targeting of conservative groups to question whether it can fairly and efficiently carry out its other responsibilities.

Former Gov. Mike Rounds (R) could see a primary challenge in his pursuit of the Republican nomination for Senate in South Dakota from state Sen. Larry Rhoden (R).

Sen. Brian Schatz (D-Hawaii) has landed the endorsement of Hawaii's largest public-sector union, a boost for his Senate campaign against Rep. Colleen Hanabusa (D-Hawaii). Read more...

Markey leads 54 to 41 percent, with 4 percent undecided in the Boston Globe poll.

The former Florida governor said his parents are "split" about a 2016 bid.

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