WASHINGTON -- Rick Santorum dropped out of the presidential race on Tuesday, but he likely lost his opportunity for the Republican nomination in February.

For a few weeks following a trio of big wins on Feb. 7, Santorum looked like he might win the Michigan primary on Feb. 28 and send the GOP nomination process into orbit.

But his tendency to speak off the cuff, in a uniquely provocative way, about cultural and social issues kept alive the image of Santorum as a “moralizer in chief” as a Wall Street Journal op-ed labeled him. And key GOP voters who had been vacillating between him and Mitt Romney bolted to the former Massachusetts governor, handing Santorum four successive losses in industrial Midwest states in a month.

Santorum’s campaign manager, Mike Biundo, defended his boss in an interview Tuesday night.

“We liked him the way he was. I think we won 11 states because he was honest,” Biundo told The Huffington Post. “We had no business, with the amount of money that we had, to be in this thing. I mean, it usually doesn't happen, you know? He carried us with sheer energy, adrenaline and hard work.”

“We had a good campaign team, and we had a great candidate. I'm honored to have worked for him,” Biundo said.

But in those four states -- Michigan, Ohio, Illinois and Wisconsin -- Santorum demonstrated an inability to expand his base of evangelical Christians by attracting support from upper-income, more moderate and less religious Republicans.

The Illinois loss on March 20 was the beginning of the end. Wisconsin on April 3 made it crystal-clear that Santorum was done. But it was Santorum’s Feb. 28 loss in Michigan that cost him the initiative and a chance at becoming the true frontrunner.

“If he would have come out of there, he would have carried Ohio. And then Michigan and Ohio combined, I think he would have been on a roll,” Ohio Attorney General Mike DeWine, who endorsed Santorum, told HuffPost Tuesday. “But that didn't happen.”

There were a few reasons Santorum lost Michigan. Romney’s money advantage was a significant factor. He outspent Santorum two to one. Romney’s roots in the state also helped him.

But Santorum cost himself key support by his own lack of message discipline. Despite Biundo’s defense, there was conflict within the campaign between those who wanted Santorum to rein himself in and those who wanted him to continue speaking his mind.

At times, Santorum showed glimmers of a message that had the potential to connect with a wider swath of Republicans.

As he traveled to Steubenville, Ohio, on the morning of Feb. 20, Santorum was flying high. A little over 60 hours earlier, DeWine -– a former U.S. senator -– had withdrawn his endorsement of Romney and switched his support to Santorum.

There was a sense that, after Santorum’s stunning wins in Minnesota, Missouri and Colorado on Feb. 7, he was on a few steps from putting Romney’s candidacy in mortal peril.

Santorum was ahead of Romney by five percentage points in the national polls. In Michigan, Santorum was ahead of Romney in polling of the state’s voters by five percentage points, 35 percent to 30 percent in the Real Clear Politics average.

Santorum spoke to a crowd of a few hundred inside Froehlich's Classic Corner, a restaurant in the former steel mining town on Ohio's eastern border, near his home state of Pennsylvania.

He gave one of the more interesting speeches of the campaign, an address that raised questions about the degree to which Santorum's political philosophy had shifted away from a focus on government-oriented solutions to problems such as poverty, crime, disease and dysfunction.

"If government is going to get smaller, then people have to get bigger," Santorum said. "And that means they have to stretch out more, they have to do more things. But how beautiful is that? How beautiful is that that you're going to have to do more to help those in need in our society?"

As he has for years, Santorum challenged the libertarian wing of the Republican Party.

"You have a lot of folks in our party who say, 'Cut government, cut taxes, everybody will be fine,' as they go off to the Hamptons for the summer,” he said.

“No!” Santorum thundered. “Go to the Lower East Side for the summer. Help out those in need in our society. Take the gift that God has given you and plow it back in, not to the government any more, but to your neighbors in your community.”

This was a message with a soul, an appeal to freedom and to people’s better instincts, and simultaneously an acknowledgement of the question that many ask of those who want to shrink government: "Then what?"

Combined with Santorum's focus on reviving manufacturing, there was potential in these words to attract fiscal conservatives who want less government regulation and taxation, along with religious values voters, libertarian-minded Republicans, and blue-collar voters of both parties.

And it stood in contrast to Romney's uninspiring promise to reprogram the economy. Romney's core message had so far failed to connect or rouse conservatives so much that one well-connected Republican consultant who supports Romney called his candidacy "a campaign about nothing."

However, Santorum drifted away from the “people have to get bigger” line. He talked about variations of that idea, but not consistently.

And Santorum committed a number of gaffes in the crucial weeks leading up to Michigan that reinforced the idea that he would be an easy match for President Barack Obama in a general election. During that time he was sidetracked by the issue of contraception and harped on the separation of church and state. And after Michigan, he swerved into talking about regulating pornography.

“It was just such a natural part of his persona, playing up the social conservative candidacy, that it was very tough for him to kind of move to a second level,” said Saul Anuzis, a former Michigan GOP chairman who was a big supporter of Romney in the state. “That's what always caught him, over and over again.”

The day after his trio of big wins on Feb. 7, Santorum accused Obama of having "an overt hostility to faith.” On Feb. 18, he said the president had a "phony theology."

On Feb. 12, Santorum's appearance on NBC's "Meet the Press" generated headlines about past comments that he considers contraception "not OK." Even though Santorum said on the show Sunday that he would not ban contraception as president and that he was not focusing his campaign on social issues, that was what drew the most attention.

On Feb. 21, the day after Santorum's speech in Steubenville, he was blindsided by The Drudge Report, the conservative news aggregation site, which dredged up audio of Santorum speaking about Satan to a Catholic university in Florida in 2008.

On Feb. 25, Santorum called Obama a "snob" for saying that most Americans should go to college. And the next day, two days before the Michigan primary, Santorum said former President John F. Kennedy's speech on the separation of church and state made him want to "throw up."

Santorum may have been leading in the Real Clear Politics average when he gave his Feb. 20 speech, but at that point the numbers were already slipping away. The poll average on Feb. 21 showed Santorum's lead down to 33 percent to Romney's 32 percent. By Feb. 24, Romney had regained the upper hand in Michigan.

Santorum's candidacy regained life on March 6, when he won Oklahoma, Tennessee, and North Dakota, and then took the lead in Ohio –- another industrial, blue-collar Midwest state -– around 9 p.m. on election night. Yet Romney eked out a win in Ohio, narrowly avoiding disaster for the second straight week.

Santorum's wins in Mississippi and Alabama on March 13 again revived his hopes. But in his third attempt at winning a big Midwest state with large cities, Santorum again was rebuffed in Illinois on March 20, this time by double digits.

Santorum's propensity for verbal missteps showed up again in March, first with a comment in Illinois that he did not care about the unemployment rate, followed by his hurling of a profanity at a New York Times reporter near the end of the month.

In mid-March, a statement on Santorum’s campaign website about more closely regulating Internet pornography drew the attention of the press. And instead of brushing off questions about the issue, Santorum engaged on it for a few days, despite advice from his wife Karen to stop answering such questions.

An experienced Republican operative, who asked not to be identified, summarized the cumulative effect of Santorum’s numerous statements.

"It just reinforces that he wants to be the moral conscience of our country, and nobody's looking for Big Brother," the Romney supporter said. "And even though I tend to agree with him, people don't want Washington in that role. It's problematic.”

Henry Barbour, a Romney supporter and fundraiser for his campaign, said Tuesday that Santorum was “someone who is more easily painted as too focused on the social issues.”

“That was a big reason why Santorum couldn't quite ever get over the hump to move from serious threat to strong contender for the nomination,” Barbour told HuffPost.

Biundo rejected the notion that his candidate was to blame for the numerous flare-ups.

“It wasn't messages that he was necessarily driving. He was saying the same things on the stump that he was always saying, but it would be a little thing here or a little thing there that somebody would grab onto and then they would try to make something out of it,” Biundo said.

Biundo did acknowledge that Santorum wasn’t always as relentlessly on message as other candidates in the race.

“He's someone who speaks from the heart,” Biundo said. “I'd rather have that than somebody that's pre-programmed that always says the right thing.”

Santorum, in announcing his decision to suspend his campaign, indicated that he was motivated as much by promoting values as he was by winning votes.

“Over and over again we were told, ‘Forget it, you can't win,’” he said Tuesday. “We were winning. We were winning in a very different way because we were touching hearts, we were raising issues that well, frankly, a lot of people didn't want to have raised.”