Strange things are happening in Republican politics. People are playing out of role. And a primary campaign that was not supposed to be about big issues could well turn out to be just that.

Last year Gov. George W. Bush was implicitly criticizing the Republican Congress for being immoderate. This year the Republican Congress is casting itself as moderate and restrained on the issue of tax cuts. Bush meanwhile offers a tax cut plan so big that his leading opponent for the party's presidential nomination, Sen. John McCain, calls it "fiscally irresponsible."

On the same day last week that McCain and Bush were sparring in New Hampshire over taxes, the House Republican leaders were announcing they would push only modest tax cuts at the beginning of this session. Their new package would cost $135 billion over a decade, a big comedown from the $792 billion tax cut bill the Republicans passed and Clinton vetoed last year.

"The Republican leadership just flat out doesn't want a food fight this year," says Rep. Mark Sanford (R-S.C.). "And the belief is that a large tax cut would most certainly lead to a food fight."

Rep. Ray LaHood (R-Ill.) was unsuccessful last year in trying to persuade his leadership to break the big tax cut bill into small pieces that might appeal to voters. He is elated with the new approach. "The polls showed the American people weren't interested in that big huge bill," he says. "They were interested in a balanced budget and paying down the debt. We were just getting pulverized on this 'tax cut for the rich' stuff."

Which raises the question: Why is Bush going out on a limb with a tax cut that would cost at least $1.1 trillion over a decade? "I don't quite know why he's doing it," replies LaHood, a strong Bush supporter, "except maybe he thinks it's something you have to do to win the party's nomination, raise money and the like."

If House Republicans are playing shrewd general election politics, Bush is playing primary politics. He's assuming Republican voters are Pavlovian: The guy with the bigger tax cut wins.

Bush is not only the "tax cuts, so help me God" candidate. He can't imagine circumstances in which he wouldn't cut taxes. "If there is a recession, it's important to cut the taxes to make sure our economy grows," Bush said in last Thursday's debate in New Hampshire. "It's also important to cut the taxes when there's apparent times of plenty as an insurance policy against an economic slowdown."

Read that carefully. Bush is saying cut taxes when times are good and cut them when times are bad. After a few economic cycles, the government wouldn't have a dime. Maybe that's the point. Someone should ask him: Was his father wrong as president to sign a tax increase that, along with the Clinton tax increases, helped eliminate the deficit and create today's surpluses?

McCain, in the meantime, is making arguments barely heard in Republican presidential politics since Bush, the father, attacked Ronald Reagan in 1980 for "voodoo economics." McCain's sound bites will bounce back in Democratic ads should Bush win the nomination.

"It's fiscally irresponsible to promise a huge tax cut that is based on a surplus that we may not have," McCain said in Friday night's debate in South Carolina. And it was McCain, not some Democrat waging class warfare, who said: "Gov. Bush's tax plan has 60 percent of the tax cuts for the wealthiest 10 percent of America."

McCain raised the ante on the tax question over the weekend. Better to talk about taxes than Washington's ways of doing business. McCain insisted that limiting tax cuts and paying down the debt were the truly "conservative" ideas.

The smart Republican money says Bush, not McCain, is making the right short-term calculation. But should McCain manage to defeat Bush in tax-hating New Hampshire, of all places, we will know that the era of Reagan-style tax cutting is over, even in the Republican Party. The House Republican leaders may be ahead of Bush on this one.