After Rick Santorum's victories in Tuesday's Alabama and Mississippi primaries, Mitt Romney told Fox News, "We're not going to go to a brokered convention."

But those who put their money where their mouths are, buying contracts on the Intrade.com online prediction market, assess the picture much differently. The latest Intrade.com probability that the Republican nominee will be selected in a brokered convention is 21.5 percent. This same probability stood at 5 percent in early February.

Ed Rollins, the veteran campaign manager and consultant who ran President Ronald Reagan's 1984 re-election campaign to a landslide victory, wrote after Santorum's winning performance: "It's now clear, it's a fight all the way. ... We haven't picked half the delegates yet and there is no inevitable winner."

It's significant that there is so much talk about a brokered convention when the current primary system is designed to avoid exactly that and when it hasn't occurred in years.

Perhaps the question worth re-asking is why Romney -- well into his second presidential campaign, with financial resources many orders of magnitude greater than his opponents' -- remains so weak.

Three major trends are worth noting, all of which are unflattering to the Romney candidacy.

One is that the Republican Party itself has become more conservative over the last decade.

In a 2000 Gallup poll, 62 percent of Republicans identified themselves as conservative. By 2011, this was up to 71 percent. So, in his own party, Romney's tepid conservative credentials hurt him.

What seems to be sustaining his candidacy, beyond his prodigious financial resources, is a notion that a more moderate Republican candidate will do better in the general election against Barack Obama. But this is also a dubious assumption.

The second major trend is that independent voters also have become more conservative. In 2000, 29 percent of independents self-identified as conservative. By 2011, this was up to 35 percent.

Third, the number of voters identifying themselves as independent is at an all-time high of 40 percent.

Gallup explains this surge in independents reflects "record levels of distrust in government" and "unfavorable views of both parties."

So, over the last decade, voters overall have become more conservative and more sensitized to looking for authenticity in a candidate.

Romney comes up short on both counts. His conservative credentials are easily questioned.

And at a time when voters put a premium on authenticity, a candidate like Romney doesn't sell well. He comes off as the political equivalent to a 1997 Aqua song with the lyrics: "I'm a Barbie girl in the Barbie world. Life in plastic, it's fantastic."

The attempt to offset all this with the claim that, as a successful businessman he knows how to fix the economy and restore prosperity, also stands on feet of clay.

Reagan stands as the leadership icon for turning the nation around from recession and inflation to prosperity. He had no background as a businessman. His strong suit was his understanding of, and absolute commitment to, conservative principles.

President Jimmy Carter, who had a background as a successful businessman before becoming governor of Georgia, led the nation to the brink in the 1970s. Reagan defeated him in 1980.

As Karl Rove convincingly argued in The Wall Street Journal this week, Barack Obama is a weakened candidate.

Voters disillusioned with the Republican Party, and looking for the kind of authenticity I've mentioned here, voted for Obama in 2008. Now it's clear they got a boilerplate liberal who, like Carter, has also brought our nation to the brink.

Republicans have a real opportunity to restore credibility as a party and deliver the kind of candidate that the nation needs.

It's why the conservative opposition to Mitt Romney, despite being massively outspent, remains strong and credible.

Far from being over, this Republican race is just getting started.