WASHINGTON — While a soldier in Iraq and Afghanistan, Tom Cotton wielded some of the military’s most sophisticated firearms. Today it’s letters that appear to be Sen. Cotton’s weapon of choice.

He fired off a missive read ’round the world this week that has catapulted the lanky, 37-year-old freshman senator from Arkansas into the spotlight, to the forefront of the debate over a nuclear deal with Iran and possibly, just possibly, to the head of the Republican presidential class of 2020.

Cotton wrote a letter to Iran’s leaders – co-signed by 46 other Republican senators – warning them against a nuclear deal with the Obama administration and asserting that any pact probably wouldn’t survive once President Obama left the White House.

The White House condemned the letter as a “flagrant, partisan attempt to interfere.” The New York Daily News blasted Cotton and his fellow signatories as traitors in boldface type. More than 160,000 people signed a petition demanding that Cotton and his colleagues be brought up on charges of violating an 18th-century U.S. treason law that “forbids unauthorized citizens from negotiating with foreign governments.”

Rep. Jared Polis, D-Colo., in a tweet, dismissively called Cotton “Tehran Tom.”

But for those who know him, and conservatives who love him, the letter was Typical Tom.

‘PALIN WITH A HARVARD DEGREE’

To admirers, Cotton is the conservative dream from central casting: a farm-raised, Harvard University- and Harvard Law School-educated former 101st Airborne Division member who isn’t afraid to tell it like it is. “Sarah Palin with a Harvard degree,” in the words of a Salon article last month.

“If the Koch brothers tried to grow a politician in a laboratory, it would have grown Tom Cotton,” said Janine Parry, a University of Arkansas political science professor.

What you get, according to acquaintances and observers, is a different kind of Republican, one who appeals to tea party and establishment wings of the party.

Unlike newer senators such as Rand Paul, R-Ky., who sometimes question American intervention overseas, Cotton is an unabashed hawk.

“He really does want to take to task elements of his party who press for isolationism,” said Jay Barth, a politics professor at Hendrix College in Conway, Ark. “He wants to stake his claim on the foreign policy front.”

Cotton offered a preview of things to come at a hearing last month where he blasted Obama’s desire to close the detention center at Guantanamo Bay.

“We should be sending more terrorists there for further interrogation to keep this country safe,” he said. “As far as I’m concerned, every last one of them can rot in hell. But as long as they don’t do that, they can rot in Guantanamo Bay.”

But his hawkish stance also found him siding with Obama. As a member of the House of Representatives, he and Rep. Mike Pompeo, R-Kan., wrote an opinion piece in The Washington Post in 2013 urging fellow Republicans to back the president’s plan to use military force in Syria.

“Congress has its own constitutional duty to defend U.S. interests, and those interests shouldn’t be neglected simply because we have doubts about Obama,” the two lawmakers wrote.

Cotton was raised on a cattle farm in Dardanelle, Ark. – population 4,693 – by parents who were Democrats who voted for Bill Clinton for governor and president.

TURNED AGAINST LIBERALISM

Their son gravitated toward Republican conservatism. He told The Atlantic last year that Clinton’s presidency, particularly “the tax increases that passed in the summer and fall of 1993, and also cutting and running from Mogadishu after the battle of Mogadishu” turned him against liberalism.

At Harvard, Cotton connected with the small core of conservatives there, particularly government professor Harvey Mansfield. He introduced Cotton to like-minded students and academics, such as Stephan and Abigail Thernstrom. Cotton served as a researcher for the couple.

“He’s super-smart, a man of integrity and a straight talker,” said Abigail Thernstrom, who served on the U.S. Commission on Civil Rights during George W. Bush’s presidency. “You may not like what he has to say, but what you see is what you get.”

Cotton joined the Army after the 2001 terrorist attacks and saw action in Iraq and Afghanistan. While deployed, he wrote a scathing letter to The New York Times complaining about a story on the Bush administration tracking terrorist financing.

“By the time we return home,” he wrote, “maybe you will be in your rightful place: not at the Pulitzer announcements, but behind bars.” The letter went unpublished, but it became a hit on conservative websites.

After leaving the Army, Cotton went to work in 2009 for McKinsey & Co., a management consulting group, and contemplated a run against then-Sen. Blanche Lincoln, D-Ark.

Instead, he successfully ran for an open House seat in 2012. He took on Sen. Mark Pryor last year and defeated the Democratic incumbent in red state Arkansas by 17 points.

Arkansas Republican state Sen. Bart Hester said Cotton’s letter to Iran had increased his stature back home and among conservatives nationwide, raising questions about a White House run.

“He’s already 7 feet tall and bulletproof,” Hester said of the 6-foot-5 Cotton. “And his mystique continues to grow.”