More and more democrats now see Jimmy Carter as a Republican at Heart, but long ago Rep. John Rhodes (R-Ariz), the shrewd House Minority Leader, perceived that the Democrats were stuck with a mugwump - that is, a politican who breaks faith with his own party or, at least, is out of step with it.

Well over a year ago, after Carter sternly lectured the Democratic congressional leaders on the need to balance the budget and slice government spending. Rhodes said, "The president is sounding foe all the world like the Republican platform. I hope this means he's joining the fiscal conservatives, if he is, he will be welcome."

As it turned out, it's doubtful if Carter would nave anu major congressional victories to speak of today had not the Republicans come to his rescue. As Sen. Jake Garn (R-Utah) says, "he has come up here and got the Republicans to bail him out on the Turkish arms embargo and on the [Mideast]plane sales," and, he could have added, the Panama Canal Treaty.

Actually, there's nothing very unusual in Republicans embracing Democratic mugwumps. Right now the acknowledge favorite for the 1980 GOP presidential nomination is Ronald Reagan, who for most of his life was an active Democrat and a liberal one at that. If Reagan falters, the mantle could fall on John Connally, the former Democratic governor of Texas and former secretary of the navy under Lyndon Johnson.

Many GOP veterans haven't yet forgotten how still another mugwump, the late Wendell Willkie, supposedly a reformed Democrat, snatched the 1940 Republican presidential nomination from the conservative jaws of Thomas E. Dewey and Sen. Robery A. Taft, "Mr. Republican" himself.

A dozen years later, the Republicans finally regained Dwight Eisenhower, a nonpolitical war hero who first became famous serving under Democratic presidents, and probably could have had the Democratic nomination for president if he had sought it.

In the White House, Ike was a disappointment to "dyed-in-the-wool" Republicans, for he was much more concerned with husbanding his personal popularity than with rebuilding the GOP. Today, Democratic leaders are similarly disappointed with Carter, only more so, for they feel that the president is not just self-centred, but has deliberately dissociated himself from the liberal traditions embraced by every other Democratic president since 1932.

Carter's post-election turn to the right was signaled in a private White House advisory composed by Patrick Caddell, the president's personal polister. "We have an opportunity," he told Carter,"to co-opt many of their [the Republicans'] issue positions, and take away large chunks of their normal presidential coalitions."

Carter took it from there. After his first State of the Union message, Sen. Barry Goldwater (R-Ariz.) said, "I made that speech in 1964 [as the GOP presidential nominee], and I was defeated." Since then, Carter has taken an even harder conservative line than former president Richard Nixon, on both domestic and foreign issues of significance such as detente with Russia.

Carter, says Sen. Paul Laxalt (R-Nev) "is turning into an indisapensable ally in our effort to revive Republicanism." And "in the eyes of businessmen," adds the chairman of the National Association of Manufacturers, Carter "has very good instincts."

Caddell warned Carter that his toughest opposition would come from an "antiquated and anarchronistic" group of "traditional liberal" and "young Turk" Democrats. Not surprisingly, Sen. George McGovern (D.S.D.) was the first Democrat to attack Carter publicly for acting like a Republican president. Carter said he was "thank-ful" that the criticism was "confined to one person."

The president, however, was whistling in the dark. Democratic candidates everywhere are currently avoiding Carter like the plague. In greater New York, one political columinist reports, "it's requires a profile in courage for a Democrat to mention the president, and if reports from the hinterland are to be credited, the same goes around the country."

Richard Reeves, a respected political analyst, who admits voting for Carter, quotes a Wyoming Democratic leader as saying, "Yeah, we hate Carter. After a while, even a dog knows the difference between being tripped over and being kicked." Out in Colorado, Rep. Tim Wirth, like other Democrats in the region, is keeping his distance from the president, whose adminstration, he sadly observes, "is a disaster." And so it goes.

In the 1976 presidential primary a Carter speech writer, RobertShrum, made the front pages when he quit and warned that the candidate was a Republican at heart, and also accused him of being manipulative and deceitful.

But did he really get the nomination under false pretenses? It's only fair to note that as far back as July 31, 1970, when Carter was running for governor of Georgia, he said, "I was never a liberal. I am and have always been a conservative." There, it seems, is the real Carter.