After winning the primaries in New York, Pennsylvania, Rhode Island, Delaware and Connecticut on Tuesday night, Mitt Romney delivered a peroration in Manchester, New Hampshire, awkwardly titled “A Better America Begins Tonight.” In it, Romney claimed the mantle of GOP nominee and declared the general election season underway. He focused on the themes he has clearly been planning on emphasizing in the contest against President Obama: a return to American greatness economically and in global power. He talked, in a way he never did in the primaries, about the financial struggles of single mothers, military veterans and recent college graduates. He also took the same standard Republican positions—in favor of privatizing the public school system, crippling unions and eliminating pension and health benefits for public workers—and reframed them as advocating for fairness. (For example, “we will stop the unfairness of government workers getting better pay and benefits than the taxpayers they serve.”) This is all part of his pivot to the center, coinciding with an emphasis this week on appeals to Latinos and young voters

But how did Romney get here? Is it true that, as his opponents and detractors in both parties have claimed, he is only the nominee because he bought the nomination?

Every time Mitt Romney won a primary, his opponents churlishly carped that he was only able to win by outspending them. “To defeat Barack Obama, Republicans can’t nominate a candidate who relies on outspending his opponents 7-1,” wrote Newt Gingrich in a typical missive after Romney won the Illinois primary on March 21. 

Even when his opponents won, they would warn potential donors that any failure to give could result in Romney’s purchasing the next round of contests. On February 8, fresh off an evening of upset victories in Colorado, Minnesota and Missouri, Rick Santorum blasted his e-mail list, writing, “I saw what Mitt Romney and his team did to Newt Gingrich after he won South Carolina. They amassed millions of dollars for his campaign and his Super PAC—outspending his opponents nearly 5 to 1! This month will be no exception. They’re going to come after us now—because Romney doesn’t have a clear conservative vision for America that he can run on.”

Throughout the Republican primary process, Democrats were eager to make the same point. “With Super Tuesday Looming, Mitt Romney’s Vast Spending Advantage Gives Him an Edge but His Blatant Hypocrisy and Extreme and Out-of-Touch Positions Will Be His General Election Kryptonite,” wrote Democratic National Committee executive director Patrick Gaspard in a March 6 memo.

So did Romney, as his opponents in both parties contend, buy the nomination? Not necessarily. Political scientists and strategists say that it is difficult to prove causality between spending and results in a presidential primary. “It’s really hard to measure the effects of spending in primary elections, because if you look at a general election it’s easy to figure out expectations without money spent: you look at partisan lay of land. With primaries there’s no expectation going in,” says Jonathan Bernstein, a political scientist who writes A Plain Blog About Politics. “How do you assess your baseline? Without that, it’s really hard to figure out what effect money had.”

Bill Mayer, a professor of political scientist at Northeastern University and an expert on campaign spending goes even further. “You literally can’t buy a nomination,” says Mayer. “Money just by itself isn’t going to do anything unless you’ve got some underlying connection with the electorate. There are lots of examples: Phil Gramm 1996, John Connolly in 1980, Steve Forbes.”

When you combine Romney’s campaign spending with that of his Super PAC Restore Our Future, he heavily outspent other Republicans and their Super PACs on advertising. According to data compiled by a rival campaign, through April 3, when the last competitive primaries were held, Romney had outspent his two main opponents by a factor of more than four to one. Romney and Romney Affiliated PACs spent $53.54 million against $11.99 million spent by Gingrich and Gingrich Affiliated PACs and $9.53 million from Santorum and Santorum Affiliated PACs.

But is that proof that if Romney had spent only $10 million that Santorum or Gingrich would be the nominee? Or is fundraising as much a measure of strength as a cause of it? The expert consensus is that Romney raised more money because he was the front-runner and he had a better organized fundraising operation. “Generally money comes from party actors,” says Bernstein. “That’s an effect of candidate doing well in the first place.” And while Romney might not have electrified the Republican electorate in the way President Obama did for Democrats four years ago, neither did his opponents. “If this had been Sarah Palin running, we all think she would have raised tons of money,” says Bernstein. “That would be either because she was way more popular than Santorum at the grassroots level or because she is popular among some segments of organized groups. What Santorum brought to the table apparently is zero of those things.”

While pundits generally assert that Romney is disliked by many Republicans, his fundraising advantage may speak to the fact that he was widely seen as the best choice they had. “You can argue that with stronger opponents it would have been quite different,” says Mayer, “but given this particular field you clearly can argue that he was liked by some portion of the electorate.”

“Romney was doing well before he or outside groups spent a dollar,” says one Republican strategist. “In fact, candidates often started falling behind when their Super PACs waded into the races. Money can certainly affect name recognition and it can drive poll numbers for a while. But there are diminishing returns. The seventh million dollars is not nearly as valuable as the first million dollars. Ultimately, earned media, grassroots word-of-mouth and field operations matter much, much more.”

But there is general agreement as well that spending can matter at the margins. There were key states where Romney’s spending coincided with a reversal in polling trends. In Iowa and Florida, Romney trailed Gingrich and pulled out a victory after dropping a money bomb of negative ads targeted at him. In Ohio and Michigan, Romney looked vulnerable to Santorum and eked out wins after vastly outspending him. “Does infrastructure matter in presidential primary politics? Yes, if you’re within a few yards of the goal line,” says Patrick Ruffini, another Republican strategist. “If you’re behind the 20, probably not. [In Romney’s case] it made a marginal difference.”

In other words, it is entirely possible that had Romney not had a spending advantage, he would have narrowly lost some states he narrowly won. It’s worth noting that Romney also gained his fundraising advantage through far greater reliance on a smaller network of large donors. As Frank Rich recently wrote in New York, “The Center for Responsive Politics has calculated that just 10 percent of Romney’s donors for 2012 have been from among the [sic] hoi polloi (those contributing $200 or less)—compared with 52 percent for Santorum, 48 percent for Gingrich, and 45 percent for Obama.” So it’s not accurate to say that Romney’s fundraising advantage perfectly reflects popular sentiment.

But even so, that doesn’t mean Romney would not have been the GOP nominee had spending been more equal. Can anyone convincingly argue Santorum would have won in New Hampshire or Illinois if Romney hadn’t outspent him? More realistically, the race would simply have gone on for longer. Santorum would have stayed in the race until now, but probably dropped out once Romney drubbed him in Tuesday’s Northeastern primaries. “If I had to single out one variable that seems to affect the results more than anything, it wouldn’t be money, it would be region,” says Mayer. “Romney lost the South, ran very close in the Midwest, he trounced Santorum in the Northeast and pretty well trounced him in the West as well.”

Unlike races for the House of Representatives, presidential primaries are amply covered in national media and in the local media of the states when they are being held. Consequently, Romney’s more significant advantage than fundraising might have been receiving a larger share of news coverage, and more positive coverage, than his opponents’. As Ari Melber has documented for The Nation, Fox News had a tendency to stop covering Romney’s opponents and mainstream outlets also favored Romney. “Santorum became non-person on Fox before Wisconsin,” notes Bernstein. “Michele Bachmann became non-person on Fox in August. That may be more important than paid advertising.”

It can be hard to imagine Romney, so wooden and blatantly disingenuous, being appealing to anybody. It’s an especially comforting notion to his opponents that he can win only if the Republican financial and media establishments force him on the public. But it isn’t so. While those institutional advantages helped him cross the finish line, the truth is that Romney wouldn’t have won if he hadn’t been popular enough to only need a little extra edge. His future opponents ignore that at their peril.