Are the Democrats going soft on Ronald Reagan's foreign policy for fear of looking "soft on communism"? Yes, says Hodding Carter III, a shrewd observer who served as Jimmy Carter's State Department spokesman. At least, he wrote recently in The Wall Street Journal, he hears voices "abroad in the land, urging a me-too foreign policy on the opposition party."

The one that really bugs him, it seems, is that of Ben Wattenberg, writing in The Post. Calling Wattenberg a "neo-Democrat," Carter placed him at the forefront of the "accommodators" who think it would be "wrong as well as fruitless" for the Democrats to challenge a Reagan foreign policy that Carter thinks is a "total, flaming disaster."

Now there's nothing new about Democrats arguing among themselves, even over such an issue as whether it's wise to argue with the Republicans. But this argument could be crucial to the character of next year's electioneering--so much so that Carter's case seemed worth a closer look.

Sure enough, Wattenberg did argue that the Democrats could get into a "Who lost Central America?" debate that would make the old "Who Lost China?" debate "look like a tea party" if they sabotage the Reagan administration's efforts in El Salvador. A "healthy spirit of bipartisanship" is what's needed, said Wattenberg. By way of a model, he awarded Walter Mondale "two cheers" (a standing ovation coming from Wattenberg) for his recent foreign and defense policy speech: "It showed that a liberal Democrat could be both tough-minded and critical of the president."

A closer look at the text of Mondale's speech seemed in order. And taking it from the top (for all of six paragraphs), you could see what Wattenberg meant. Mondale opened with a ringing denunciation of Soviet leaders as "cynical, ruthless and dangerous." He hailed a "bipartisan consensus" on first principles: "Let Moscow make no mistake; on the issues of survival and security Americans do not divide."

Except, unfortunately, when the consensus is "unraveling" which, you abruptly discover by paragraph seven, is precisely what's happening: "Ironically, tragically, inadvertently but unmistakably, President Reagan is weakening America."

Mondale said he could go into a whole catalog of bungles ("loose talk" about winning nuclear wars; assorted arms control mishaps; the European/Siberian pipeline "disaster"; botched diplomacy with China; a defense budget so far out of line his own Republican Party "won't go near it"). But he really didn't want to talk about "symptoms." He wanted to diagnose the "disease."

And the disease, it develops, is nothing trifling: Ronald Reagan is operating from "fundamentally flawed premises about preventing war and keeping peace."

The Mondale argument is debatable, but interesting, and forcefully set forth. It rests on a set of alleged "fallacies" in the Reagan approach, starting with the administration's presumption of American military weakness. "In the nuclear age, the perception of strength is part of our arsenal," Mondale argues. "Yet Mr. Reagan persists in telling the world we're weak" in a way that undermines the American public's confidence, scares our allies and "tempts adversaries; every time he says we're weak, he literally weakens us."

Mondale goes on to question the Reagan administration's good faith in its pursuit of arms control. He accuses it of believing that we "can win an arms race, and that we should try to." He says the president has spent too much time trying to prove our toughness to a world that doesn't doubt our power. The result is that serious questions have been raised about our "stewardship of our power."

You can take issue with any or all of Mondale's recommendations for a sounder course. He is against the MX, in favor of strengthening conventional forces to "raise the nuclear threshold." He would proceed with a long list of programs to build particular weapons "at a supportable, sustainable rate" while radically revising defense priorities.

But these are matters of detail. Hodding Carter's question is whether the Democrats are in danger of pulling punches out of political prudence. And the answer is that if the Mondale approach is Ben Wattenberg's idea of bipartisanship, Hodding Carter has nothing to fear from mushy Democratic me-tooism.