"Vote early -- and often." We hear this quip every time an election rolls around, and with good reason: Electoral fraud is as old as the ballot box itself and still happens in the United States. Just last year a judge in Washington state ruled that some 1,678 illegal votes were cast in its 2004 election -- more than enough to change the outcome of the governor's race.

Few concepts matter more in a republican democracy than the credibility of "one person, one vote." Yet no nationwide standard exists to prevent fraud at the voting booth.

Some states, including Virginia, sensibly demand photo identification before allowing someone to vote. Neighboring Maryland, meanwhile, is heading in the opposite direction. A new state law there will let anyone cast a provisional ballot anywhere in the state -- a move that could allow one person to vote in several different places on the same day.

At the end of Election Day, "Nothing is more important than the integrity of elections -- not even defeating the Republicans in November." And don't take my word for it; those are the words of Blair Lee IV, the Democratic commentator who ran his father's successful 1980 gubernatorial campaign in Maryland.

To prevent fraud in elections, the federal government should set some minimum standards. After all, the Constitution gives states the initial power to establish the "times, places and manner" of holding elections, but it specifically permits Congress to change those election procedures.

A good first step would be to require every voter to show a photo ID.

Some liberals oppose this rudimentary reform. They claim that, since the poor are less likely to have photo IDs or driver's licenses, it would impinge on their civil right to vote. But, as John Fund of The Wall Street Journal wrote in his 2004 book, Stealing Elections: How Voter Fraud Threatens Our Democracy, "when voters are disfranchised by the counting of improperly cast ballots or outright fraud, their civil rights are violated just as surely as if they were prevented from voting."

Of course, not everyone has a photo ID, and we can't allow that to prevent them from voting. But the federal government could get around this the same way Georgia has. That state recently mandated all voters show photo ID, but it will provide free IDs to anyone who can't afford a driver's license.

A bipartisan federal commission on election fraud backs this idea. In a report released last year, the Carter-Baker commission recommended that states require voters to show a card that includes, among other things, a person's legal name, address, digitally captured signature and photo.

Federal action to require ID would, in part, correct a problem federal lawmakers themselves created when they passed the Motor Voter Act. That bill was supposed to streamline the voter registration process (which wasn't especially complex to begin with). But it went too far.

Under Motor Voter, it's difficult for states to remove ineligible voters, including felons and non-citizens, from the rolls. At the same time, many people end up registered two or three times in different precincts or states.

The Illinois Board of Elections says that, "The integrity of the election process is protected by access to it." But integrity also hinges on whether those with access have legal access. Those who vote illegally or vote several times in one election cancel out ballots cast by legal voters.

Americans realize that fraud is a bigger long-term concern than butterfly ballots or outdated punch cards. A recent NBC News/Wall Street Journal survey found that 81 percent support requiring a photo ID to vote. Only 7 percent oppose the idea.

For an election to be valid, we need to know that it was fair and that everyone who voted was eligible to do so. Requiring an ID before a voter steps into the booth would be a big step in that direction.

Edwin Feulner is president of The Heritage Foundation (heritage.org), a Washington-based public policy research institute and co-author of the new book Getting America Right.