"Unheard of," Plainville Town Clerk Kathleen Sandland called it. "Remarkable."

She was referring to the turnout at Tuesday's presidential primary after 2,167 of the town's 5,367 registered voters cast ballots. The 40-percent turnout is considerably higher than previous primaries, which have been as low as 10 percent.

About 1.3 million of Massachusetts' 4 million voters were expected to participate, so the Legislature should be commended for moving up the date of the vote to include the state in the Super Tuesday voting, making it more attractive for citizens to participate. Our democracy benefits from greater involvement of its citizenry.

Still, on a day when the future occupant of the White House could well have been determined, it's a little disappointing to see more than half of the state's voters ignore the polls.

The Legislature could further improve turnout in November's general election if it adopts legislation that has lingered on Beacon Hill for years. Right now, state law requires that citizens be registered to vote 20 days before an election. Why? In the past, there had been fears of voter fraud. However, eight other states, including New Hampshire, have adopted same-day voter registration with few problems. In an era when nearly all adults have a driver's license, proof of identity and address should be all that's needed to cast a ballot.

There are legitimate concerns about funding the change. Secretary of State William Galvin, the state's chief election officer, estimates that it would cost $1 million to hire and train additional poll workers for November's general election.

Other states do not report significant new expenses, though Massachusetts, with its large urban populations, may be different. That $1 million price tag shouldn't be a barrier to greater involvement in our most important civic duty, and the federal government has funds available to help states increase turnout.

But there are compelling arguments for same-day voter registration. As elections near, voter interest intensifies. Citizens shouldn't be shut out of the process by a technicality.

The change would work, according to a soon-to-be released study by Demos, a research organization based in New York. Demos estimates that turnout in the November presidential election in Massachusetts could rise by 226,000 voters, or 4.9 percent, if people had the opportunity to register at their polling places on election day. In Plainville alone, that would mean 263 more voters would cast ballots, a prospect that undoubtedly would please Town Clerk Sandland.

Demos also notes that young people, who may be eligible to vote in their first election in November, are more likely to be shut out by the 20-day deadline. Demos estimates that turnout among those ages 18 to 25 could increase by nearly 10 percent with same-day registration.

The same-day registration bill has died more from a lack of interest than from objections. If there are legitimate concerns, we hope they are aired quickly and the issue resolved.

An opportunity to get more people to exercise their most basic right should not be ignored.