Mesa, Arizona (CNN) - Mitt Romney sought to answer lingering questions about his presidential bid and cast himself as the ideal GOP standard-bearer at an appearance before several thousand supporters outside Phoenix on Monday.
Hoping to unite the fractured party and forge ahead to the general election, the GOP candidate touted his conservative credentials and painted his Republican opponents as Washington insiders who could not effectively change the nation's capital.
Without mentioning their names, he alluded to former Sen. Rick Santorum and former House Speaker Newt Gingrich as men who had "spent their life entirely in government."
"Congressman Paul was a doctor, then went into government, but the other guys have spent their life entirely in government," Romney said of his Republican opponents. "And in my view it's helpful to have been involved in two businesses, an Olympics and a state, and to run all - and to have a chance to run those as an executive.
"We elected in President Obama someone who had never run anything, who had never been a leader," Romney continued. "We're not going to do that in the Republican party. Let's not nominate someone who hasn't done anything and has not been a leader."
Romney's front-runner status was shaken last week when he lost a trio of states to Santorum, prompting concerns the candidate had not won over the party's conservative base.
But days later, Romney triumphed in two tests, winning Maine's caucuses and coming in first in a straw poll of an influential conservative advocacy group in Washington. Arizona could be another crucial win for the White House hopeful, who is favored to take the state February 28.
Speaking to an enthusiastic audience at his get-out-the-vote rally, Romney criticized President Obama's new budget proposal for costing too much and failing to tackle ballooning spending on entitlements such as Social Security and Medicare.
"This president miraculously today with his new budget had nothing to say about making sure that those programs are solvent and permanent," Romney said. "If I'm president, I will save Social Security and Medicare and make sure they do not kill the future generations with excessive taxes."
Romney also emphasized his stance on social issues such as gay marriage while he was governor of Massachusetts, saying he had taken a conservative position in a largely-Democratic state.
In a reminder of the general election to come after Republicans choose a nominee, at one point during Romney's speech the chants of protesters outside the Mesa amphitheater became audible. The group supported a path to citizenship for illegal immigrants via the so-called Dream Act.