Presidential campaign speeches are always more important for what they say to the country than they are for their effect on their local audiences. So it is important that, one week before the election, President Reagan finally did what only a president can do: articulate a general theme that frames the issues favorably to his party's cause. He avoided, in this speech in Raleigh, N.C., mistakes he has made in earlier campaigning: emphasizing the opposition's issues, talking about lots of little local issues and making contentious statements on issues such as the nuclear freeze, which are not central for most voters.

Reagan's change of emphasis in his speech here Tuesday might not have been obvious to many of the faithful -- the country folks with American flags pinned on their shoulders, the affluent teen-agers with their alligator sweaters and monogrammed shirts. But his new theme should become evident in TV ads the Republicans will run Sunday and Monday.

"We are changing the direction of America," the president said in Raleigh. "Our critics are playing with people's fears, trying to scare them into believing that things will get worse, so their own political fortunes will get better." But, he said, "America has a future of courage and hope -- hope that grows brighter as more people respond to the drop in inflation, tax rates and interest rates." He portrayed the election as a choice between hope and fear, between policies that are beginning to work and policies that have failed.

This "hope vs. fear" theme avoids concentrating, as his earlier, "nonpolitical" TV speech on the economy did, on the Democrats' strongest issue, unemployment. True, the president tried then to put employment in perspective by arguing that in four other respects the economy was improving. But this "four out of five ain't bad" defense is just that, a defense; it let the Democrats set the terms of debate. And the great value of a president as a campaigner is that he can set the terms of the debate himself.

Nor did Reagan divert attention from his main theme. His speech contained only one perfunctory paragraph on the abortion and school prayer issues which are so important to North Carolina's Sen. Jesse Helms. And despite Helms' past support and prowess as a fund-raiser, he found himself placed on the far end of the platform, away from the president. Helms was mentioned only once in the president's speech, in the 16th paragraph.

The Democrats, in denouncing Reaganomics and unemployment, have staked their fortunes on the assumption that the election is a referendum on the present. Reagan, by trying to stir voters' hopes and accusing the opposition of exploiting their fears, is staking his party's fortunes on the assumption that a midterm election depends on voters' assessment of the future.

This will not produce a massive Republican victory: views on the future are mixed. But they are more favorable to Republicans than views on the present, and most voters will concede that it takes more than one or two years for any macroeconomic policy to work.

Shifting from "four out of five ain't bad" to "hope vs. fear" spotlights the Democrats' weak spot: their own lack of specific alternatives. Democrats have a few short-term changes, mostly marginal, and a few long-term policies, which no one is prepared to act on.

In the meantime, it seems entirely fair for Mr. Reagan to suggest, as he is pleased to do, that we can judge what the Democrats would give us from what they gave us when they had full control of the government, in 1977-80.

Yet even if it turns out that the president has framed the issues in a way that helps his party's flagging fortunes, the picture one gets of Reagan as a political strategist is not entirely reassuring. For a couple of months he took the lazy course of following everyone's advice and squandered many chances to frame the issues his way.

Now he has decided on a single theme, one simple enough to capture the attention of an apolitical public and plausible enough to convince not only the party faithful holding hand-painted signs in the far-from-cavernous Raleigh Civic Auditorium, but, he hopes, the far larger audience of what he called, to cheers, "the network evening blues" and those Sunday and Monday TV ads.

Is it too late? Republicans all over the country are running every man for himself -- a vivid contrast to the united party of 1980--and Democrats may have persuaded many voters to treat their votes as a verdict on the present. My own guess is that Reagan's "hope vs. fear" theme, if properly emphasized by the Republicans, will be enough to prevent the Democrats from making the large gains that have seemed possible in the last few weeks. If so, what might it have done for Republicans earlier?