Obama, with the advantages of an incumbent, is well ahead of Romney on fund-raising, organization, and broad pitches to voters. So Romney can be expected to spend part of his time during the next three weeks trying to catch up. There's a break in the primaries until April 24, when several Northeastern states vote.
Romney also must start thinking about a running mate and strategy to amass the 270 electoral votes needed to win the White House on Nov. 6.
The former Massachusetts governor must prepare to put his imprint on the Republican National Committee and figure out how to achieve unity with a conservative base that has resisted his candidacy. In the general election, party loyalists will be counted on to raise money and get out the vote.
"I do think the Romney team is thinking about how they put in place their fall campaign," said Terry Nelson, a former top aide to President George W. Bush. "But they clearly have some contests to get through, so they won't be able to turn their eyes entirely to that."
There's little question that Romney will clinch the nomination in June, if not earlier. He has a wide lead in the race for the 1,144 delegates required to secure the GOP nomination. But chief rival Rick Santorum says he'll press on at least through the end of the month. Pennsylvania, which he represented in the House and Senate, votes April 24, along with Connecticut, Delaware, New York, and Rhode Island.
In hopes of convincing Republicans it's time to rally behind Romney, leading Republicans such as Sen. Marco Rubio of Florida and Rep. Paul Ryan of Wisconsin have endorsed him recently; both are viewed as potential running mates. Rhode Island Gov. Don Carcieri has said he would back Romney and Iowa Gov. Terry Branstad may announce his support soon.
Romney is sounding more like a general election candidate each day. "It isn't about one person or about even one party," he said last week. "We're Republicans and Democrats in this campaign, but we're all connected with one destiny for America."
After a break for the Easter holiday, Romney is expected to plunge back into fund-raising in New York and South Florida. That's none too soon for Republicans, given Obama's fund-raising advantage.
"Ultimately, the thing we have to focus on is getting the general election money raised," said Brian Ballard, of Florida, one of Romney's top fund-raisers.