FORMER PRESIDENT Gerald Ford is itching for a second crack at President Carter, convinced that this time he could win. Ford's main credentials for the presidency, as he sees it, are that he left the economy in good shape, whereas Carter's policies have brought the nation to the edge of disaster.

"When I came into office, the inflation rate was 12 percent, and my policies brought it down to 4.8 percent," Ford boasted to CBS News.

Since then, of course, inflation has zoomed close to the 20 percent annual level, and the economy betrays more instablity than it has for 35 years, or since the end of World War II. The nation seems to be threatened with double-digit inflation for the rest of the decade.

A look at Ford's 1975-76 record shows that he began his White House career with what even he conceded later was a wrong-headed approach to the economy.

Failing to see the depths of the recession that had gained momentum at the end of 1974, Ford put forward the embarrassing "Whip Inflation Now" (WIN) program, including a 5 percent tax increase. But to give Ford credit, he quickly shifted gears away from the WIN proposals, and offered a large antirecession tax cut. Then he accepted an even larger one, designed by Congress, and this gave Democrats a basis for saying that recovery in 1975 was achieved despite Ford's policies rather than because of them.

At the end of 1975, Ford finally signed an extension of the tax cut, after (incredibly) vetoing it the first time around. His general philosophy was to reduce the federal deficit and tokeep the scope of government limited. This was reflected in a string of vetos by Democratic proposals -- emergency job bills, housing programs and accelerated public works.

By early 1976 the economy had responded to the tax stimulus and was buzzing along nicely with real growth at 7.5 percent and inflation under 4 percent. Republicans like Murrary Weidenbaum could exult: "I sure like the combination -- it's the hallmark of a healthy recovery and sound expansion."

BUT THE PROBLEM was that the expansion didn't last at that rate. And this proved to be the undoing of Ford and -- perhaps in a sense -- of the economy under Carter. By the time the unemployment rate hit 8 percent in the fall of 1976, Ford adviser Alan Greenspan was confessing to a "pause" in the economy, and candidate Carter was impatiently whipping together an activist, expansionary set of proposals that he put into effect in 1977 after taking office.

In hindsight, it turns out that the liberal establishment which pushed a big expansion on Carter was wrong. Just as Ford and Greenspan originally misassessed the strength of recession in 1974, Carter and Economic Council Chairman Charles Schultze misread the strength of inflationary forces in 1977.

The big political hang-up, of course, was high unemployment, and Carter was urged by labor and the Democratic left to do even more than he did. But the stimulus program Carter did send to Congress in 1977, coupled with energy moves that merely deregulated prices, needed a lid of some kind. Carter, trying to prove his manhood to Wall Street, refused to consider even the mildest kind of wage and price guidelines at a time they might have been effective.

Some Carter insiders admit privately the situation had been created for a potential "blow-off." They mistakenly chose to be good soldiers, and remained silent.

WHAT FOLLOWED was a series of up-and-down, ad-hoe actions and juggled forecasts, most of them wrong. One day it would be tax reform; the next, tax cuts. First, zero-based budgeting and a balanced budget; then, record budget deficits.

Two months after submitting his economic plan and budgets for 1980 and 1981, Carter is in the process of junking both. Last week, press assistant Jody Powell said Carter, like Ford, will be a veto-minded president. What next?

Can Ford or any other president get the inflation genie back in the bottle?

It will take, as well, a gutsy Congress, responding to a president with the kind of leadership that Carter has failed to display in his 3 1/2 years in th White House. Carter doesn't learn. He makes the same mistakes over and over again. His advisers are stale, and they reject new ideas.

In this circumstance, Sen. Ted Kennedy might be making more headway if it were not for Chappaquiddick. But the crisis course for the economy, coupled with Carter's continued indecisiveness, will give him real trouble against any Republican in November.