A time bomb that could bring major changes to California politics has been set in place and is likely to become explosive before the next presidential election.

Right now, Democrats are licking their chops over the potential benefits they expect from same-day voter registration, a practice that’s been allowed in nine other states and will become the norm here the year after the secretary of state, California’s top election official, certifies a new high-tech voter registration database. That will take several more years, but most likely will be done before the fall of 2016.

Same-day registration is a system hated just now by Republicans, who say it will invite fraud even though ballots cast by same-day registrants will be considered provisional, with election officials in all counties having until the end of the election canvassing period (about a month post-election) to determine whether new registrants were really eligible to vote.

Democrats believe the new system will provide them hundreds of thousands of new voters, perhaps enough to decisively control several swing districts created in the 2011 redistricting plan devised by the Citizens Redistricting Commission, which got its first test this fall.

They anticipate that myriad citizens who have been uninvolved and not interested enough in government to register to vote by the current deadline two weeks prior to Election Day will take heed at the last minute and go vote.

Republicans, meanwhile, see the practice as inviting illegal immigrants and shady sorts into the voting booth. For one example, they ascribe the 2008 election of Democratic U.S. Sen. Al Franken of Minnesota to “over 1,000 illegal Election Day registrations.” Franken won election by fewer votes than that.

The predicted effects of same-day registration are reminiscent of what so-called experts believed in 1976, when California okayed unlimited voting by absentee ballot. Previously, absentee voters had to certify they were either too ill to vote in person or would be away on Election Day. The practice has grown to the extent that almost half of all ballots here this fall were cast by mail, voters getting the chance to mark their ballots as they made up their minds proposition by proposition and candidate by candidate.

Republicans licked their chops at the prospect of all those absentee ballots, knowing they had always before dominated the smallish mail vote because the GOP has traditionally done better among high-wealth groups that travel a fair amount.

Victorious Strategy

That’s how it went, too, for the first six years of unlimited absentees. Democrats learned how to stage ballot-marking parties and began to send absentee voter applications to targeted groups, many of whom were registered but didn’t vote very often. Gradually, Democrats began winning more and more mail votes, until these days they consistently take a majority of them statewide.

Might this work in reverse with same-day registration, with Republicans figuring out new ways to entice party sympathizers who don’t often vote to come out at the last moment? There’s every possibility for that.

A similar delayed reaction was already felt this fall from Gov. Brown’s 2011 signature on a bill allowing online voter registration for anyone who already has a signature on file with the Dept. of Motor Vehicles.

Again, Republicans lamented potential fraud, as 22,000 persons registered by computer on the first day it was possible last September. By the registration deadline, almost 1 million new voters had been added to the rolls this way, mostly among people who found registering in person inconvenient.

Legislative Republicans voted against this step, but it may turn out to benefit the party in the long run, again because of that wealth factor: It takes a certain modicum of cash or credit to buy a computer and get online with it. That’s probably why most online polls taken without randomized sampling come out favoring the conservative side of whatever issue is up for question.

But Who Will Benefit?

“If I wanted the ideal conditions for voter fraud, I would select the California laws for an A-plus,” said Steven Frank, conservative blogger and former head of the California Republican Assembly. “Will these new voters be verified? When they ask to be permanent absentee voters, will anyone ever check to see if these are real people?… All this has the potential to end honest elections.”

Just as no one could anticipate the eventual impact of unlimited absentee voting, no one can now be certain who will be the long-term beneficiary of the newly liberalized voting laws. It depends on who comes up with the best system for taking advantage of the system to register and turn out voters who might lean their way.

Mr. Elias may be contacted at tdelias@aol.com. His book, “The Burzynski Breakthrough: The Most Promising Cancer Treatment and the Government’s Campaign to Squelch It,” is now available in a soft cover fourth edition. For more Elias columns, see www.californiafocus.net