The political media may have welcomed the closing of polls on recent evenings in Florida, Michigan, Arizona, and Ohio with an air of suspense, but the members of Mitt Romney’s team knew they already had more votes than their opponents. In the case of Florida, Romney’s advisers believed Newt Gingrich would need an extraordinary Election Day performance to catch up; in Arizona, they were certain it was mathematically impossible for either Gingrich or Rick Santorum to do so. Even a late surge or Romney’s own collapse was unlikely to redraw the outcome. “You want to get as many people to vote absentee-ballot as you can—it saves money and banks votes,” says Rich Beeson, Romney’s political director. “So no matter what happens in the last week you have votes in the bank they can’t take away.”

Once-meaningful distinctions between early voting, voting-by-mail, and absentee ballots are being erased as 32 states now offer voters the chance to cast their ballot before Election Day without a justifying excuse (as traditional absentee balloting required). It probably amounts to the most radical change to American voting culture since the abolition of poll taxes. In 2008, one-third of Americans are believed to have voted by a method other than showing up in person at a polling place on the first Tuesday in November, some doing so as early as September.

Romney’s canny and competent handling of these varied early-voting processes this year has helped him accumulate a seemingly insurmountable lead in delegates. He is running the only modern, professional campaign against a field of amateurs gasping to keep up, and nowhere is that advantage more evident than in his mastery of early voting. Capitalizing on early-voting procedures demands formidable investment up front in the service of later savings.

When state authorities searched for ways to update their election procedures after the chaos of the 2000 recount, many decided to expand the window for voting. Political scientists, campaign consultants, and election administrators speculated about who stood to benefit most. Those who said such reforms would boost democratic participation cited an economic logic: Reducing the inconveniences involved in voting would, in effect, lower its cost and make it appealing to more people. A decade later, there is scant evidence that new opportunities to vote have significantly affected the electorate: The limited research in the area suggests that those who are already predisposed to vote—and make up their minds well in advance—are the most likely to seize on the lower costs to cast a ballot on their own schedule.

But early voting has changed electoral economics. In effect, candidates have to administer Election Day operations for a period as long as two months. In general elections, those costs are often saddled by party organizations that can share the benefits across multiple candidates. In primaries, campaigns are on their own, and the expansion of early voting reinforces existing advantages for campaigns that are rich, skilled, and experienced.

“It looks like the better organized campaign does better,” says Christopher B. Mann, a former Democratic campaign consultant and party official who ran early-vote programs and now studies them as a University of Miami political scientist. “If you look at the primaries, it’s largely to Romney’s advantage because he has the funding, the infrastructure, and the sophistication to take advantages of things in a way the other candidates couldn’t.”

In Florida, that meant running a campaign at full tilt for six weeks in a state where it is particularly expensive to do so. Once the absentee-ballot period opened in late December, Romney’s data team downloaded a daily list made available by Florida election officials and compared names of those who had requested ballots against those that the campaign’s state-specific microtargeting models had identified as probable supporters. Those who matched up were subjected to the gauntlet of get-out-the-vote pressures usually reserved for the last weekend before Election Day: a barrage of phone calls and flurry of mail. “If you know a voter has an absentee ballot in their hand, you’re running a full-fledged GOTV program,” says Beeson.

At the same time, Romney sustained a six-week-long ad campaign aimed at persuading those his microtargeting models scored as undecided. State officials compiled daily updates of voters who returned their ballots by mail and others who cast them at in-person voting centers, allowing Romney to launch a dynamic strategy that refined his persuasive appeals to court the dwindling ranks of those who had yet to make a choice. “You’re running parallel programs. You run a persuasion program and a GOTV program,” says Beeson. “We adjusted every day. You continually shrink your GOTV universe and talk to less and less people.” By the time Newt Gingrich, then his top rival, established a Florida operation, he was catching up on both fronts—with a significant portion of the electorate having already locked in their decision. Preliminary analyses, like this chart of Miami-Dade County results assembled by Reed College’s Early Voting Institute, show Romney collected a much larger share of his votes from absentee ballots than his opponents.

Ohio election officials did not make it so easy for campaigns before its Super Tuesday primary. Each of the state’s 88 counties handled their own early-voting lists, in different formats, and Romney managed a fleet of volunteers responsible for pulling in the daily updates and integrating them with the campaign’s other data.

The primary race has thus far taken place in states where Romney’s staff had plenty of advance warning to learn the vagaries of early-vote rules and—as they did in Florida—develop well-planned strategies to compete under them. The coming contests may offer Romney fewer chances to exploit his advantages in early-voting states, including such large delegate troves as California and Texas. Romney’s resource advantage over Santorum appears to be shrinking, likely cramping his organizational prowess. Forced to improvise in states where he had not planned to still be contesting the nomination, Romney is often setting up his operations after early-voting has begun.

In Illinois, which votes next week, it has been possible for Illinoisans to vote by mail since Feb. 29 and in person at select locations since March 5. Yet there is little evidence that Romney has done any more than his rivals to accumulate intelligence on which voters have already cast ballots. An official at the Illinois Board of Elections says none of the Republican presidential candidates have set up a state-level political committee, a prerequisite for being granted a password to the website where the board releases continuous updates. “It’s a pretty arduous task,” Illinois Republican party boss Pat Brady says of the challenge of developing a system to monitor early voters in his state. “The candidates haven’t been here long, and will probably be relying mostly on television advertising.”

Yet Romney has likely already reaped enough gains from mastering the system in earlier states to ensure he is the only Republican who could enter the Tampa convention in August with enough delegates to become the nominee. “If you look at Gingrich and Santorum, who spent their political careers in the Nineties, they’re dinosaurs to the new way of campaigning,” says Mann. “Romney was much better prepared going into 2012 for how people vote today.”