Des Moines — A man who could have run for president but passed threw his support behind a fellow Republican who is running on Wednesday.

Sen. John Thune endorsed GOP presidential candidate Mitt Romney at a packed and well-publicized event at the Des Moines office of Nationwide Insurance. Thune represents South Dakota, which shares a bit of its border with Iowa’s western region.

Before Thune spoke, Romney explored two themes with the crowd on this Thanksgiving eve. The former Massachusetts governor gave thanks to key things that are part of America’s virtues: including military service members who protect the nation, the “American spirit,” his family and his faith.

Yet in a quick transition, Romney also explained what he is not thankful for: a president whose policies he sees as ruining the nation.

“The president has not been able to bring the country together. And on some of the most important issues that we face in the world, he’s simply withdrawn and not stepped forward as a leader,” Romney said.

As an example, the candidate repeated his recent criticism of President Obama’s lack of involvement with the super committee that failed to reach agreement on a deficit reduction deal this week.

Romney laid out what he called choices between the U.S. “living within our means” and the $600 billion in defense cuts triggered by the lack of an agreement.

“With those two things at stake, looking down the road at a Greece-type situation, or … gutting of our military, our president decided to go campaigning, go around the world making visits, finding people to blame,” Romney said.

After the candidate spoke, the South Dakota senator officially announced his support.

“I’m just happy that you would accept my endorsement with congressional approval ratings at like 9 percent in some polls,” Thune joked. “When I had this conversation with him, about whether or not to endorse him, I guess what I should have said is, ‘I’ll come out either for you or against you — whichever helps you the most.'”

The senator also praised Iowa’s importance as holding the first-in-the-nation presidential contest on Jan. 3.

“I appreciate the important role that you play in our political process,” Thune said. “I know how seriously you take the responsibility that you have as the first in the nation to start this political process to make sure that you do that job well.”

And Thune criticized President Obama.

Using the president’s 2008 campaign themes of “Hope and Change,” Thune said, “I think now that we have had an assessment, over the past three years, it’s pretty clear that that hasn’t worked out so well.” The senator cited what he called the president’s failed record on jobs, weakening home values and government debt.

“It’s going to take the right kind of leader to get us out of that hole. And that’s why it’s so important that we nominate somebody that can go into that campaign, toe-to-toe, face-off with this president and talk about a different vision for the future of this country,” Thune said.

“He is a guy who has turned failing things around.” Thune added, saying that Romney has turned around businesses, the 2002 Olympic Games and the Massachusetts economy.

Thune’s endorsement could carry weight in western Iowa, home to many social conservatives. Yet it comes amid news that some key figures from that group held a secret meeting to brainstorm ways to derail Romney’s campaign in Iowa and beyond.

At the end of his opening remarks, Romney also explained one more bit of thanks.

“A year and a half ago I was sitting down with a couple of my friends, political friends that were giving me advice, and I said: ‘Who do you think is going to be the toughest competitor that I’d face if I run for president?'” Romney said.

“And the number one answer came about some senator from South Dakota that I’d never met.”

“I’m so lucky he didn’t run,” Romney said.

Thune decided against running for president in February.