Gerald Herbert/AP Photo

Mitt Romney's wins in Michigan and Arizona helped him pick up a big chunk of delegates, but more importantly, it has washed away talk of a Republican party desperate for a "white knight" to jump into the primary.

Even so, one GOP bigwig finds Romney's narrow Michigan win "unconvincing." Romney, this GOP strategist told ABC News, won "by being totally negative. Where's the hope and optimism? He's becoming a human wrecking ball. A receding tide sinks all boats."

Moreover, Romney doesn't have an easy road ahead of him this coming week.

March 3: First stop, the Washington state caucus on Saturday. Romney hasn't had a very good track record when it comes to caucuses - he's won two and lost three. Santorum, of course, has won nothing but caucuses, and recent polling suggests Santorum is leading in the Evergreen State.

March 6:  Super Tuesday: The most recent polling shows Romney trailing in Ohio, Oklahoma, Georgia and Tennessee. Combined, those states hold 243 delegates.

Moreover, as we saw tonight in Michigan, and in ABC/Washington Post polling this week very conservative voters are not sold on Romney.

In Michigan, 30 percent of those who voted in the primary identified themselves as very conservative. Romney lost the very conservative vote to Rick Santorum by 14 points.

On Super Tuesday, very conservative voters will become a bigger part of the electorate. In 2008, very conservative voters made up 38 percent of GOP primary electorate in Tennessee. They made up 39 percent of the vote in Oklahoma, and 32 percent of the vote in Georgia.

But, if we've learned anything from this primary campaign, it's that momentum is king. A good election night can move numbers - quickly.

The first place we'll be looking for signs of "Mitt-mentum" will be in Ohio. The state has a similar make-up to Michigan. There are a smaller percentage of very conservative voters and evangelicals than there are in the southern states.

The most recent Quinnipiac Poll showed Santorum with a seven point lead in the Buckeye State. But, just a month earlier, Romney had a nine point lead in the state.

Look for both the Santorum and Romney camps to hunker down in Ohio over the next week. Santorum, the former Pennsylvania Senator who has been touting his blue collar roots, can't afford to lose two Midwestern states. If Romney loses here, talk about his vulnerability will continue as will the hand-wringing by GOP insiders.