(CBS News)- two states with electorates similar to those that have proven favorable to him in the past. Maryland's affluent and educated primary voters once again supported Romney, and in Wisconsin he continued his winning streak with Midwest voters.
Romney may have also been helped by a sense of inevitability. More than eight in 10 Wisconsin voters expect him to be the Republican nominee -- even two-thirds of Santorum backers think that's the case. Only three in 10 of Santorum's own voters said their candidate will win the party's nomination.
And while he didn't win them in Wisconsin, Romney made inroads with very conservative voters and evangelicals, groups he has struggled with even in other Midwestern states where he has been victorious.
As he has in many past primaries, Romney won wealthier voters (those with household incomes of $100,000 or higher), but he also edged out Santorum among lower income voters, those earning less than $50,000. Voters age 65 and over have often been a part of Romney's winning coalition, and 52 percent of those voters backed him in Wisconsin.
Romney won the support of college graduates in Wisconsin, but he also bested Santorum among voters without a college degree - a group Romney was unable to carry in Ohio and Michigan, despite wins in those states.
In states where exit polls have been conducted, Rick Santorum has failed to win when the percentage of white evangelicals is below 50 percent, and that was the case in Wisconsin. Thirty-seven percent of Wisconsin voters identified as white evangelicals, and while Santorum got their support, it was not enough to pull off a win in the state.
Romney won the support of both men and women, and performed especially well with working women, defeating Santorum by 18 points among this group.
Fifty-five percent of Wisconsin voters were Tea Party supporters and 48 percent of them supported Romney; 37 percent backed Santorum.
Romney's opponents have attacked him incessantly for the Massachusetts health care plan he signed into law as governor, but when Wisconsin voters were asked which candidate they trust to handle health care policy, Romney was the top choice with 36 percent, followed by Santorum with 31 percent.
As voters have throughout this campaign, Wisconsin primary voters chose the economy as their top issue, and Romney beat Santorum by 14 points among those voters. Defeating President Obama was the top candidate quality, and 67 percent of voters who picked it went for Romney; only 23 percent backed Santorum.
Most Wisconsin voters decided on their candidate a while ago, but a third made up their minds in the last few days. Those late deciders broke narrowly for Santorum (42 percent) over Romney (38 percent).
Strength of Support
In Wisconsin, 55 percent of Romney's voters said they strongly favor him, an improvement over his showing in Illinois where just 42 percent said that. Forty-four percent of Romney voters say they either have reservations about him, or support him because they dislike the other candidate choices.
Less than half (46 percent) of Santorum voters strongly favor him, and a 53 percent majority either has reservations about him or supports him because they dislike the alternatives.
Many of Santorum's Wisconsin supporters question Romney's conservatism - 64 percent of them say Romney isn't conservative enough. At the same time, just a third of Romney's voters think Santorum is too conservative.
In Maryland, 48 percent of voters said they had incomes of $100,000 or more - making this the most affluent electorate among the states that have held contests so far. Romney won 53 percent of the vote among this group in Maryland; he has won among high income voters in every state so far except for Georgia, South Carolina and Louisiana.
More than half - 57 percent - of Maryland's primary voters reported having a college degree - another voting group that has supported Romney in many states. He won 53 percent of their vote.
Looking ahead, most of Maryland's Republican voters plan to support whoever their party's candidate is in November. Eighty-five percent of Romney voters said they would definitely support the Republican nominee in November; just 14 percent said they would probably do so or they would do so only if Romney is the nominee. Among those who voted for Rick Santorum, 73 percent said they would definitely vote for the nominee in November, and 26 percent said they would probably do so or would only vote for Santorum as the party nominee.
As in Wisconsin, a majority (71 percent) of Santorum's voters said that Romney is just not conservative enough.