Amid the Cabinet reshuffling, little attention has been paid to the appointment of Bush campaign manager Ken Mehlman as Republican National Committee chairman. But Mr. Mehlman’s appointment could turn out to be as significant for our politics as Condoleezza Rice’s is likely to be for foreign policy.

If Karl Rove was the architect of George W. Bush’s thumping re-election victory, Mr. Mehlman was the structural engineer who turned the plans into reality. Mr. Mehlman’s great achievement was to create a largely volunteer organization of 1.4 million people who turned out the vote in counties big and small for Mr. Bush. He managed this task the way Rudolph Giuliani managed the NYPD: by requiring metrics – numerical goals, validated by independent parties – to measure the work being done every week.

This enabled the Bush organization to plug holes and provide psychic rewards for those doing good work. No one (including Mr. Giuliani himself) thought Mr. Giuliani could cut crime in half in New York City; very few thought that Mr. Mehlman could produce 10 million new votes for Bush. But Mr. Giuliani did it, and so did Mr. Mehlman.

The surge in turnout was unusual for what was, after all, a rerun election. Turnout was down in 1956 when Dwight Eisenhower faced Adlai Stevenson a second time. Turnout was down in 1996 when Bill Clinton faced Ross Perot and a decorated World War II veteran a second time.

Many people figured they had made the decision already and didn’t need to go to the polls again. Not so in 2004, when Mr. Bush faced a second liberal Democrat who had spent much of his career in the Senate. With the absentee votes in California and Washington finally counted, it appears that overall turnout was up 12%. John Kerry’s popular vote was also 12% above Al Gore’s. But the popular vote for Mr. Bush was up a stunning 20%. Before the election, some liberal commentators were claiming that Mr. Bush would win no votes he hadn’t won in 2000. Not quite: He won 10 million more.

Mr. Bush’s popular vote was up 23% in the 13 battleground states that decided the election. Mr. Kerry’s paid-worker, union-led turnout drives in central cities nearly matched that – his vote was up 21% over Mr. Gore’s in the battlegrounds. But that wasn’t enough to outdo the Bush volunteer efforts in the make-or-break states of Florida and Ohio.

Elsewhere, Mr. Bush had a bigger edge. His popular vote was up 21% in safe Bush states and 16% in safe Kerry states, compared to 12% and 5% for Kerry. The Bush organization literally reshaped the electorate. The 2000 exit poll showed an electorate that was 39% Democratic and 35% Republican. The 2004 exit poll, which was tilted toward Democrats, found a dead-heat: 37% to 37%. That means that Republican turnout was up 19% and Democratic turnout up only 7%. This is the most Republican electorate America has had since random-sample polling was invented.

Re-elected presidents seldom do much for their parties; certainly Reagan and Nixon didn’t. Roosevelt did, and Bush evidently intends to also. Look for Mr. Mehlman to continue engineering volunteer organizations to increase Republican turnout and further reshape the electorate. Obvious targets are New Jersey and Virginia, which elect governors in 2005. Neither was a battleground state this fall; Mr. Bush ran better in New Jersey and a little worse in Virginia than expected, and Mr. Mehlman would like to make Virginia safer and put New Jersey in play.

Then there are the 2006 Senate races in Pennsylvania, where Republican Rick Santorum could face a serious challenge, and in Michigan and Minnesota, where freshman Democrats are likely to face serious challenges. Mr. Kerry carried all three of these battleground states with just 51% of the vote. Mr. Mehlman wants to change those numbers by 2008.

Sam Walton made his fortune by selling goods at low prices in downscale rural and exurban communities where other retailers saw little profit. Mr. Mehlman won the election for Mr. Bush by increasing the Republican vote in downscale rural and exurban counties where neither party used to think many more votes could be won.

Wal-Mart is now the most successful retailer in history. Mr. Mehlman seeks to be the most successful party-builder ever. No one made much money betting against Sam Walton. I wouldn’t bet against Mr. Mehlman, either.