The Republican presidential candidate gives a video lecture in improving the country’s energy prospects in advance of primaries and caucuses in 10 states on March 6.

Republican presidential candidate Mitt Romney says the Obama administration fought "religious liberty," remarks that the president's campaign called "disgraceful."

Asked about a speech he gave three years ago, the Republican presidential candidate says, “I believe in good and evil”--and staying on message.

Republican presidential candidate Newt Gingrich has scrapped plans to campaign in Michigan for that state’s Feb. 28 primary, and will instead spend most of his time in states with primaries that fall on Super Tuesday, March 6, his campaign confirmed late Tuesday.

Seeking to blunt attacks by rival Mitt Romney, GOP presidential candidate Rick Santorum points to his work exposing scandals in Congress.

A 2008 speech by Rick Santorum in which he described an attack by Satan on the United States is getting renewed scrutiny after several Web-based publications circulated audio and text of his remarks over the holiday weekend.

Mitt Romney will unveil a new, "bolder" tax plan either on Wednesday night at the CNN debate in Arizona or at his Detroit Economic Club speech on Friday, CNBC's Larry Kudlow wrote Tuesday in National Review. More details on Medicare and Social Security are coming, too.

After calling President Obama “the most dangerous president in modern American history” over the weekend, GOP presidential candidate Newt Gingrich continued his attacks on the president early Tuesday, criticizing him over his national security record.

TULSA, Oklahoma – Barack Obama is “the most dangerous president in modern American history” and the nation's safety can't be assured until he's ousted, Newt Gingrich said Monday.

CINCINNATI -- Mitt Romney accused Rick Santorum on Monday of making a major contribution to reckless Republican spending, helping the GOP “spend like Democrats,” by voting repeatedly to raise the debt limit while he was in Congress. The attack came as Romney stood next to a Republican senator who voted last year to raise the debt limit.

Rhetorical firebombs are becoming par for the course for Republican Rick Santorum’s presidential campaign. This one apparently was an accident.