DARDANELLE —Spilling the worst-kept secret in Arkansas politics Tuesday, Republican 4th District Congressman Tom Cotton announced his bid for the U.S. Senate seat held by Democratic incumbent Mark Pryor.

Cotton, a Harvard-educated Army veteran of the Iraq and Afghanistan wars who just recently passed his six-month milestone in politics, will challenge Pryor, a former state legislator and attorney general who followed the legacy of a father beloved in Arkansas politics into public service, in 2014.

"I joined the Army to serve our country and to defend our freedom overseas," Cotton said at a barbecue dinner his campaign orchestrated in his hometown in Yell County. "That’s why I ran for Congress: To serve you and to defend our freedom and our Constitution in Washington. And that’s why today I’m announcing my candidacy to be your United States senator."

With a group of relatives and a giant American flag behind him, Cotton, clad in jeans and a dress shirt with rolled-up sleeves, told a crowd of about 350 people in the Dardanelle Community Center that Pryor has voted for President Obama’s agenda 90 percent of the time, on issues from immigration to health care to the economic stimulus.

"It’s time that we said, ‘Enough.’ Arkansans deserve a senator who will stand with them and stand up to Barack Obama," Cotton said to cheers from the appreciative audience.

Cotton, 36, also addressed accusations by Pryor and other Democrats that he is driven by personal ambition and has not paid his dues.

"Some people say I’m a young man in a hurry. Well guess what? They’re right. When problems are this severe, I’m in a hurry to try to solve them," he said.

Also speaking at the event were Cotton’s father, Len Cotton, and U.S. Rep. Tim Griffin, R-Little Rock.

"The farmer of the best crop of Cotton to ever come out of Yell County (is) Len Cotton," Griffin said, to laughter and cheers.

In this western Arkansas community of about 4,800, several people said Tuesday they hope to see the Cotton defeat Pryor.

Pawnshop owner Lance Adams, who said he does not know Cotton but knows his parents, said he has voted for Pryor in the past but supports Cotton because his values align more closely to Adams’, such as his strong opposition to abortion.

"I go by B-I-B-L-E," Adams said.

Print shop owner Barry Sims, who said he has known Cotton his whole life, called Pryor "too liberal" and praised Cotton for casting politically risky votes.

"He’s holding true to his beliefs," Sims said.

The 2014 Senate race will represent a battle for the only Arkansas delegation seat in Washington currently held by a Democrat against an upstart Republican who is still in his first year representing Arkansas in Congress. It also could be for control of the Senate, which means a multitude of campaign spending ahead by both parties and other interested parties.

Talking to reporters at the barbecue, state Republican Party Chairman Doyle Webb touted Cotton’s candidacy.

"I think he reflects the reviews of most Arkansans. Mark Pryor is out of step with Arkansas and her values, and Tom Cotton is in step," Webb said.

State Democratic Party spokeswoman Candace Martin said in a written statement, "After seven short months in Congress, Arkansans only know Tom Cotton as an arrogant congressman whose blind ambition has hurt women, farmers, students, and seniors."

Though the Cotton camp was mum, several sources, including U.S. Sen. John Boozman, R-Ark., confirmed last week that Cotton would announce his Senate bid Tuesday.

He has been widely expected to take on Pryor since he began his meteoric rise by sweeping to the open 4th District seat last year after leaving work as a management consultant with New York-based McKinsey & Co. and returning home to the family farm.

He brushed aside two GOP primary opponents without a runoff last year and won 59 percent of the vote against Democrat Gene Jeffress of Louann in the November general election for the 4th District seat vacated by Democrat Mike Ross, who is now running for governor.

Since entering Congress, he has been in the national media spotlight as a spokesman for conservative issues and as an unrelenting critic of the Obama administration.

Democrats on the state and national levels have been hammering Cotton’s voting record for months, and in recent days have labeled the freshman Republican congressman as a blatant political opportunist who has put ambition ahead of the interests of Arkansans. The party launched a website this week, MeetTomCotton.com, to highlight his opposition to such issues as the House farm bill, lowering student loan rates and the Violence Against Women Act, and on attempts to cut Social Security and Medicare.

Pryor, 50, is the son of former Arkansas Gov. and U.S. Sen. David Pryor. He earned a law degree from the University of Arkansas and worked in private practice until entering politics. He served two terms in the state House in the early 1990s and one term as state attorney general from 1999-2003. He defeated incumbent Republican Tim Hutchinson in the 2002 U.S. Senate race and did not draw a Republican opponent in 2008.

Pryor earned a reputation as a Senate moderate but has been a target for Republicans since voting for Obama’s health care overhaul and is now considered by the GOP among the nation’s most vulnerable congressional Democrats. He has been hounded by groups on the left and right for positions he has taken, including his opposition to legislation to expand background checks for gun purchases in the wake of the Newtown, Conn., shoot shootings.

Cotton enters the contest trailing Pryor in the campaign cash, though neither side is expected to be short on money in a high-stakes race in which independent groups also will likely flood the state with attack ads.

Pryor had more than $3.9 million in his campaign treasury at the end of June. Cotton had just under $1.1 million, which could be used for a re-election run or a Senate bid.

Cotton’s announcement is likely to start a wave of political declarations from candidates for his seat and for others that could be vacant as a result.

Republican Lt. Gov. Mark Darr and Arkansas House Majority Leader Bruce Westerman, R-Hot Springs, both of whom have said previously they would be interested in running for the 4th District seat should Cotton run for Senate, attended the barbecue but declined to make any immediate announcement.

Darr said he would announce his plans "sooner rather than later." Westerman said he would make an announcement at a rally in Hot Springs next Tuesday.