Many of the states that allowed early voting this year experienced few delays on Election Day, and now federal election officials, lawmakers and voting experts say people in every state should have the same privilege.

There is also increasing support for broadly expanding voter registration rolls, possibly by having the federal government require the states to make registration automatic for all eligible voters. Supporters say universal registration could reduce registration fraud and the confusion at the polls that results when voters are purged from the rolls.

Such a plan would be costly and technologically difficult, and it could run into resistance from Republicans who have been wary of expanding registration, citing concerns about ineligible voters being added to the rolls. Some state officials say they would prefer to set registration standards themselves.

But independent experts say easier registration and voting methods would ensure that huge crowds like those on Tuesday turn out without being discouraged by the long delays experienced in many states.

“The single most important thing that Congress can do right now is create universal voter registration, which would mean that all eligible voters are automatically registered,” said Rosemary E. Rodriguez, the chairwoman of the federal Election Assistance Commission, which oversees voting. “We also saw incredible success with early voting, and requiring states to adopt it would help as well.”

Ms. Rodriguez said universal registration would reduce the dependence on third-party groups like Acorn to sign up people and would remove the impetus for much of the pre-election litigation over who should be allowed to register.

Congress is already discussing the adoption of early voting nationwide. It now exists in 32 states in various forms.

A bill to do so was drafted last year by Senator Dianne Feinstein, Democrat of California, and its co-sponsors included Senator Barack Obama, Democrat of Illinois. The bill was tabled after receiving little support from Congressional Republicans but is likely to have a better chance next year when Democrats hold expanded majorities on Capitol Hill and Mr. Obama is president.

Early voting proved extraordinarily successful in providing people with more options to cast their ballot and in easing the strain of turnout on Election Day. It gave voters the chance to clarify their eligibility before Election Day, and it gave election officials more time to test and understand new machines and rules.

Democrats say legislation to expand registration, most likely to be introduced in the coming months, will be tougher to pass.

“A system of automatic registration, in which the government bears more of the responsibility for assembling accurate and secure lists of eligible voters, is a necessary reform,” Senator Hillary Rodham Clinton of New York, who is working on legislation intended to overhaul how eligible voters register, said Thursday. “All eligible Americans should be able to cast their ballot without barriers, and the registration problems we saw on Tuesday and during the weeks that preceded Election Day make clear that the system needs improvement.”

There are several possible methods of achieving universal registration with different roles for the states and the federal government.

Lawyers from the Brennan Center for Justice at the New York University School of Law, as well as other voting rights groups working with Mrs. Clinton on her legislation, said they had been pushing a proposal to leave control of the lists at the state level.

Their plan would require states to expand the voter registration databases that have already been created so that they include all eligible voters. To do this, states would draw information from tax records, driver’s license lists and social service agencies. The plan would also require states to update registrations whenever voters filed an address change with the Postal Service or other government agency, so the 14 percent or more of voters who move every year do not fall off the rolls.

Richard L. Hasen, an election law expert at Loyola Law School in Los Angeles, has pushed for a more ambitious plan in which the federal government would build a national database of registered voters.

“We could minimize long lines, lower the amount of election-law litigation and bolster public confidence in the process of running our elections if we turned over the job of voter registration to the federal government,” Dr. Hasen said. “If the feds were charged with registering every eligible voter, then concerns about voter registration fraud, database mismatches and provisional ballots would be seriously reduced.”

Arguments for and against such plans are very likely to fall along partisan lines, with most support coming from Democrats.

Lorraine C. Minnite, a political science professor and voting rights expert at Barnard College, said Republicans had generally resisted such efforts in part out of concern about ineligible voters like noncitizens being permitted to vote.

“But the bigger reason that Republicans have resisted expanding the franchise,” Dr. Minnite said, “is that the new people who are likely to come into the electorate are more often of lower income and are people of color, who tend to vote Democratic.”

Tom Jensen, a Democratic pollster based in Raleigh, N.C., said early voting gave Mr. Obama the edge for his narrow victory in North Carolina by offering his campaign more time to organize rides and get people to the polls. Mr. Jensen noted that Mr. Obama won early balloting by 178,000 votes but lost among Election Day voters by 165,000 votes.

“Obama had a great ground game,” he said, “but if you only have 13 hours to get everyone out, it’s much harder.”

R. Doug Lewis, director of the National Association of Election Officials, a nonpartisan group that represents local and state election officials, said his members saw this as a “state’s rights issue” and were not thrilled about any possible federal takeover of registration or new laws that required early voting. But Mr. Lewis said they would support legislation that gave states incentives to help achieve these goals.

Most state election officials see the merit in early voting, Mr. Lewis said, and have become frustrated by dealing with voter registrations being submitted by third-party organizations, often in duplicate or with errors. He said state officials believed that they could do a better job than Washington in deciding how to keep the lists accurate and whether to expand them.

But how states maintain and verify their lists has become a serious problem and led to many lawsuits around the country. Before the election, Colorado, Louisiana and Michigan were found to have wrongly removed thousands of voters from their rolls.

The Election Protection Hotline received more than 20,000 reports from states like California, Georgia, New York and Pennsylvania of voters who showed up at the polls to find they were not on the rolls. The only option for them was to cast a provisional ballot, which is not recorded if poll workers cannot find a matching voter-registration record.

In Missouri, the secretary of state, Robin Carnahan, agreed that changes were needed.

Because of long lines and confusion, “there were some people in our state who couldn’t vote, and it’s heartbreaking to hear their stories,” said Ms. Carnahan, a Democrat. “Early voting would have solved a lot of that.”

She added that while she would resist federal control over voter registration, she would support incentives for states to broaden participation and federal steps to make the process more uniform.