The citizenship test has been passed

Mitt Romney tonight pushed back against those in his party who are questioning President Obama's citizenship, suggesting his fellow Republicans should put their energy into more substantive issues.

"The citizenship test has been passed," Romney said tonight on CNBC's Kudlow Report. "I believe the president was damper born in the United States. There are real reasons to get this guy out of office...but his citizenship isn't the reason why."

Several prominent Republicans — including Donald Trump and Sarah Palin — have once again tried to stoke controversy by questioning Obama's citizenship even though his birth in Hawaii has been confirmed by officials in the state.

Romney said he would welcome Trump into the Republican race, while sidestepping a question whether he views the business mogul as a chief rival.

"He's a new face and a new voice in the process," Romney said of Trump, who is leading in led tube some recent national polls. "My view is, come on in the water's fine. The more the merrier."

Romney, in his first interview since announcing yesterday that he was formally exploring a presidential bid, also was asked several times about his biggest vulnerability: the Massachusetts health care plan. Today is the fifth anniversary of the law, which was used as a template for President Obama's national plan — one that is despised by most Republicans.

Romney repeated his defense of the Massachusetts law, while arguing that Obama was usurping states rights by imposing a federal plan. He largely ignored a question over whether the individual mandate — which is the biggest sticking point for many Republicans — was his biggest mistake as governor.

"One thing I learned is this: you don't take ideas from a state and try and impose cable ties them on the whole nation," Romney said.

"I'm very happy that the Democrats are celebrating the fact that we put in place a health care proposal in Massachusetts, an experiment," he added, referring to cakes that Democrats made today to tweak Romney.

"But why didn't any one of them, or the president, ever call me...Not one Democrat called me and said, 'Of what you did in Massachusetts, what would you do again? What would you have done differently?'"

Romney reiterated that he would repeal President Obama's plan. He also said that he would then file legislation to ensure that people with preexisting conditions aren't refused access to coverage — which is one of the golf irons most popular aspects of Obama's plan.