(CNN) -- Former Arkansas Gov. Mike Huckabee bowed to "the inevitable" and dropped out of the Republican presidential race Tuesday night after an improbable run for a politician little known beyond his home state a year ago.
Huckabee announced he was giving up his bid for the White House after John McCain swept Tuesday's contests in Texas, Ohio, Vermont and Rhode Island, giving the Arizona senator the delegates needed to claim the party's nomination in September.
"It's been a heckuva run," he said.
Huckabee urged his supporters to back McCain in November and said he has no "Plan B" for his political career. Watch Huckabee concede race »
"Clearly, things didn't go our way tonight, and we had hoped they would," he told reporters on his plane back to Little Rock. "But when the inevitable is staring you in the face, you accept it."
When Huckabee announced his candidacy in January 2007, the former Baptist pastor was best known for his dramatic weight loss. The 52-year-old governor dropped more than 100 pounds after being diagnosed with diabetes in 2003, and wrote a 2005 book called "Quit Digging Your Grave with a Knife and Fork."
A CNN poll that month showed him drawing 1 percent support among the GOP field nationwide, well behind then front-runner Rudy Giuliani. But the affable Huckabee made a name for himself with an easygoing style. He showed off his skills playing rock-and-roll bass and surprised observers with a second-place finish in the GOP straw poll in Ames, Iowa, the following August.
Huckabee went on to best former Massachusetts Gov. Mitt Romney, by then the GOP front-runner, in the Iowa caucuses January 3, placing him among the top tier of Republican hopefuls.
He lagged behind Romney and McCain in the next round of contests, in New Hampshire and Michigan, and trailed McCain in South Carolina. However, his victories in West Virginia and the Deep South states of Georgia, Alabama, Tennessee and his native Arkansas in the February 5 Super Tuesday contests helped force Romney out of the race.
"Over the past few days, a lot of people have been trying to say that this is a two-man race," Huckabee told supporters that night. "Well, you know what? It is, and we're in it."
But McCain's big wins that night gave him an ultimately insurmountable lead among delegates to the party's September convention in Minneapolis-St. Paul, Minnesota, and Huckabee faced calls to drop out and let the GOP concentrate on November's election. He refused those calls, vowing he would stay in the race until mathematically eliminated from contention.
Huckabee raised nearly $13 million during his campaign, which was far less than McCain's nearly $55 million and a small fraction of the nearly $90 million Romney spent during his unsuccessful bid, according to records from the Federal Election Commission.
"To have gone this far and outlasted so many others, I think is a remarkable story. Wish it would have ended differently, but it is what it is," Huckabee said.
Huckabee's exit leaves anti-war Texas congressman Ron Paul, a former Libertarian presidential candidate, as McCain's sole active opponent. E-mail to a friend