Former House Speaker Newt Gingrich officially ended his campaign for the Republican presidential nomination on Wednesday.

In delivering a statement on his departure from the race, Gingrich characterized his time on the trail as "a truly wild ride." He said that he and his wife Callista had "an amazing year."

Addressing the future of presumptive GOP presidential nominee Mitt Romney's campaign, Gingrich said that he's been asked whether the former Massachusetts governor is "conservative enough." He said the contest "isn't a choice between Mitt Romney and Ronald Reagan." Rather, he said in taking a shot at President Barack Obama , it's "a choice between Romney and "the most radical, leftist president in American history."

Gingrich also made critical remarks about the way things are done in the nation's capital, calling the Senate a "stunningly dysfunctional institution."

Despite hitting bumps in the road, it wasn't too long ago that Gingrich vowed to continue his campaign all the way to the Republican convention in Tampa in August. On Tuesday, he released a web video addressing his decision to abandon his presidential operation.

The Associated Press reports that Gingrich is leaving the primary contest with his campaign carrying at least $4.5 million in debt.

"I'm suspending the campaign," Gingrich said on Wednesday. "But suspending the campaign does not mean suspending citizenship."

As the race for the White House goes on, Romney said in a statement, "Newt Gingrich has brought creativity and intellectual vitality to American political life."