MIAMI — Rick Perry, George W. Bush's successor as Texas governor, was expected to make his 2012 White House run official on Saturday -- touting his state's robust job growth as a model for the struggling US economy.

Perry, who polls show running a close second behind Republican front-runner and former Massachusetts governor Mitt Romney, is a staunch social conservative who has cultivated a pro-business image since taking office in 2000.

After months of flirting with a presidential run, "the governor will make his intentions very clear on Saturday," when he visits the key primary states of South Carolina and New Hampshire, said Perry spokesman Mark Miner.

US media said Perry would formally announce he was joining the crowded field of Republicans eager to win the party's nomination to take on President Barack Obama in the November 6, 2012 elections.

A Fox News Television survey of Republican primary voters taken last week found 21 percent planned to vote for Romney while 13 percent preferred Perry. Other polls show a narrower race between the two.

"I'm very calm in my heart that this is what I'm supposed to be doing," Perry told Time magazine in an interview out Thursday, saying he had realized he "couldn't sit on the sidelines if my country's future truly is at stake."

The tough-talking ex-US Air Force pilot, who has called on God to guide the US president, advocates free trade, the right to bear arms, tough immigration policies and cuts to education and health programs to ease budget woes.

The square-jawed 61-year-old politician with a thick crop of dark hair was born to ranchers in the west Texas town of Paint Creek and began his political career as a member of the Democratic Party, changing sides in 1989.

That year, he transformed himself into a brash, unapologetic Republican -- embodying the qualities conservative leaders say Obama lacks and which Perry could exploit in a potential presidential run.

"Father, our hearts break for America," Perry prayed last weekend before a rapturous crowd of around 30,000 people gathered at a Houston stadium and thousands more watching online.

Perry, who was raised a Methodist, called on God to impart "wisdom" on the US president -- without naming Obama -- and prayed that God would "inspire" the nation's leaders, pastors, generals, and parents in "difficult times."

He will appear Saturday at a gathering of conservative activists in South Carolina, a key early contest for the Republican nod, before heading to New Hampshire, home of the first primary, and Iowa, which holds the first caucus.

His critics point out that his state has high rates of poverty, and he would likely face fire over telling an anti-tax "Tea Party" rally in 2009 that Texas might be better off seceding from the United States.

Miner later told the Texas Tribune the governor was joking and never advocated secession.

The Texas governor has all the while defended his opposition to tax hikes on the private sector, telling Time magazine: "I am a pro-business governor. I will be a pro-business president."

On foreign policy, one adviser with knowledge of Perry's thinking told Foreign Policy magazine he would portray himself as a "hawk internationalist" -- advocating more defense spending and warning about China's rise.

According to Foreign Policy, he has recently said Iran and North Korea represent "an imminent threat with their nuclear ambitions."

But in 2009, he defended his decision to lure Citgo -- the state-controlled oil firm in Venezuela, where President Hugo Chavez is an anti-US firebrand -- to move its US headquarters from Oklahoma to Texas.

"Dictators come and dictators go," but "Citgo will be around long after Chavez is gone," Perry said at the time.

"He's a cowboy," Michael Goldfarb, a former senior staffer on Republican Senator John McCain's 2008 presidential campaign, told Foreign Policy.

"You have to assume he'd shoot first and ask questions later -- which would be nice after four years of a leading-from-behind, too-little-too-late foreign policy."

Perry, a graduate of Texas A&M University with a degree in animal science, spent several years in the US Air Force, serving in Europe and the Middle East before launching his political career as a state legislator.

After serving as state farm commissioner under former governor Ann Richards and Bush, Perry became lieutenant governor in 1999. He took over the top job in the southern state after Bush was elected president in 2000.

He then was elected to full terms as governor in 2002, 2006 and again last year, on the back of the robust job growth of the "Texas Miracle" he has overseen since taking office.

Perry has been married for nearly three decades to his childhood sweetheart Anita Thigpen. They have two sons.