U.S. Senator Lindsey Graham of South Carolina, a longtime Washington insider and critic of President Barack Obama's foreign policy, said he would announce on June 1 whether he will seek the 2016 Republican presidential nomination.
"I'm running because I think the world is falling apart," Graham said on Monday in an interview on CBS. He has previously said he was "99.9 percent" sure he would run.
The South Carolina lawmaker was quoted by MSNBC as telling supporters in an email: "As an announcement draws near, I need to know you stand with me." The Washington Post quoted him as saying in the email about his "CBS This Morning" appearance.
Graham is a prominent critic of President Barack Obama's foreign policy and a close ally of fellow Republican Senator John McCain.
He was warmly received at the Iowa Republican Party's forum for 2016 White House hopefuls on Saturday in Des Moines with a mix of jokes and plain talk about America's national security.
"I'm thinking about running for president. You get a house and a car and a plane. It's a pretty good gig," he said.
While other Republicans in the 2016 field have made clear they would not have invaded Iraq given what is now known about U.S. intelligence failures, Graham offered a strong defense of then-President George W. Bush.
He said Bush acted based on intelligence at the time that said Iraq possessed weapons of mass destruction, and that he did the world a favor by toppling then-Iraqi leader Saddam Hussein.
If Graham enters the race, he would join fellow Senators Ted Cruz, Rand Paul and Marco Rubio among declared candidates for the 2016 Republican presidential nomination. Former Arkansas Governor Mike Huckabee, former Hewlett-Packard Chief Executive Officer Carly Fiorina and retired physician Ben Carson have also announced their candidacies.