The New Hampshire cops pulled over Ronald Reagan's motorcade last week for speeding. Not surprising. Overconfident recklessness has characterized much of the Reagan campaign strategy so far and his camp has paid dearly--in Iowa and, perhaps, in New Hampshire. The swaggering certainty around Reagan headquarters six months ago, even two months ago--based on the heady assumption that no Republican hopeful could possibly come within spitting distance of ol' Ron--has proved crippling.

The disaster of Iowa has shot through his campaign--softening up the tough old man and leaving him wide open for a knockout punch. But Iowa may not have turned out the way it did if Reagan had stepped on the brakes, mingled with the crowds more often, and at the very least, stopped speeding long enough to participate in the Republican debate in Des Moines in January.

Back then though, Reagan strategists were still sunning in the August polls that had Reagan leading with 48 percent and George Bush pocketing a whopping 1 percent. John Sears, Reagan's top strategist, figured it was wisest to keep his man out of the fray (judging from Reagan's predilection for erratic public behavior. Sears had a point)--and retain the image of the untouchable front-runner. "It won't do any good to have Reagan going to coffees and shaking hands like the others," Sears explained before the Iowa caucuses. "People would get the idea that he's an ordinary man like the rest of us."

So Reagan spent no more than 45 hours campaigning in Iowa, behaved almost as though he were the incumbent. The Iowans interpreted it--rightly, perhaps--as a slap in the face. They--and the Bush people--slapped back. As for the debates--which Reagan claimed he avoided because they might divide the party--58 percent of Iowa's voting adults watched that night and they all remembered--and few appreciated--Reagan's absence.

Reagan could only wince and explain that his was a "national candidacy" as he watched the returns roll in from the farm precincts of Iowa. "I'm in a different state every day--I've got a national constituency, and I've got to work to maintain that. George Bush had to stake his all on the early win," he said.

But earlier last year Reagan's national planners were saying something quite different. They were counting on knocking out any serious opposition early on--like in the first three primaries. But at the time, Sears and other Reagan backers thought only Baker and Connally could threaten the candidate. Sears brushed off Bush as a man with no constituency in the GOP. "If Reagan wins early, that's the ball game," William Russo, political coordinator for Sen. Robert Dole (R-Kan.) agreed back in October.

But the ball game is still on. If Reagan does not come away with some sure wins in New Hampshire and Massachusetts his base in the icy Northeast will be less than secure and some of the frost could spread to Alabama, Florida and Illinois--the ex-Governor's strongholds.

(Aloofness clearly didn't wash in Iowa and Reagan's managers have shifted tactics in New Hampshire.) They added more campaign stops to the Granite State schedule. But for Reagan promoters, exposure is as dangerous as isolation. The public blunders four years ago attest to that--on Rhodesia, Reagan proclaimed in 1976 that the United States should send in the troops. Or, digging back still earlier, in November 1966, when he told conservative Human Events that 'Social Security ought to be voluntary." A year earlier in the Washington Star, he offered this analysis of Earl Warren's abilities: "I think he's a lousy justice."

In a state as politically tuned as New Hampshire, Reagan's gaffes have been especially troubling. Whether they like it or not, Granite State voters are exposed to every comment and every poll. You knew what the guy from Manchester had on his mind at the Gun Owners of New Hampshire forum when he stood up to question Reagan: do you still think that ethnic jokes are funny, governor?

Meanwhile, wife Nancy--extolled by the Manchester Union Leader as the woman we all should strive to be--has contributed some complimentary remarks of her own about the "white folks." The latest University of New Hampshire poll has Reagan four percentage points behind Bush, and indicates that the gap between the two men is growing steadily. The comments are adding to a new perception: Reagan as a reeling, slipping old man, about to give way to the new, tweed-capped Superman who spent some time in Peking.

Reagan's problem is largely age--but not so much biologically as rhetorically and ideologically. He speaks from a creaking, World War II perspective; his rhetoric has a rusty edge to it--broadcast from a different, simpler day when things didn't insist on being complicated. In New Hampshire, it may prevail but in the real world, it is losing its appeal.

Reagan draws a stark battle front: the Common Man versus Big Government. But the language is no longer enlightening--if in fact it ever was. Even Thomas Paine wasn't sure who the Common Man represented and Big Government is a moldy slogan, particularly when the opponents are thrusting around "geopolitical linkage" to wow the crowds.

Wherever he goes, Reagan brings with him a deck of 4 by 6 prompting cards, printed neatly with parables and short quips. When cornered to speak on the issues, his answers are hard to distinguish from the one liners. Blockade Cuba. Give business a free hand. Forget about making deals with the Russians, Hang on to the Panama Canal. "We built it. We paid for it. It's ours and we are going to keep it."

Economics is an uncomplicated matter, Reagan assures his listeners. Just end deficit spending. "This is the single cause of inflation, and inflation is the cause of recession." (He revealed this insight four years ago in Kennet High School in Conway, N.H., before a rapt audience.)

Taxes? "The key to restoring the health of the economy lies in cutting taxes."