Rep. Dick Gephardt (search) on Wednesday called chief rival Howard Dean (search) a "fair-weather friend of the American worker" whose promises can't be trusted and motives must be questioned.

"To me, there is no room for the cynical politics of manufactured anger and false conviction. I believe in standing for something," the Missouri lawmaker said a speech that heightened his criticism of the Democratic presidential front-runner.

Gephardt, whose candidacy depends on an Iowa victory Monday, is locked in a tight caucus race with Dean and two other candidates, Sens. John Edwards and John Kerry.

"Howard Dean travels the country and yells and pounds the podium against NAFTA (search), against the secrecy of the Bush-Cheney White House, and against insider corporate deals," he said. "This is the same Howard Dean who said he 'strongly supported NAFTA,' who won't release his records as governor, and who wanted Vermont to 'overtake Bermuda' as a tax haven for companies like Enron."

An opponent of free-trade accords signed by Presidents Clinton and Bush, Gephardt appealed to his supporters in organized labor by lumping his rivals together as trade advocates.

"John Kerry, Joe Lieberman, Howard Dean and Wesley Clark, who all supported NAFTA, are now acting like they fought against it. And John Edwards supported the China deal," Gephardt said of the North Carolina senator who is making inroads on his blue-collar base.

"Howard Dean went so far as to call himself a strong supporter of NAFTA," Gephardt said. "Then he later denied it, even though he was captured on videotape saying just that."

"You can't take on George Bush if you're only a fair-weather friend of the American worker," he said.

Gephardt then launched into a list of examples that he said underscored his view that Dean flip-flops on policy for political convenience.

"The only way we can beat George Bush is to be clear about where we stand and to be truthful with the American people," he said. "It's become nearly impossible to know what Howard Dean really believes."

It is the latest in a long line of criticisms from Dean's rivals, who hope to slow his momentum with a defeat here and cut into his lead in the follow-up New Hampshire primary. Private polls of two campaigns show Clark, a retired Army general, within 10 percentage points of Dean in New Hampshire, reflecting the Arkansan's remarkable surge while the rest of the field was camped out here.

Gephardt criticized Dean for:

— Promising to give Democratic primary voters angry speeches, which will give way to cooler rhetoric in the general election. "Howard, Democrats are not animals in need of red meat," Gephardt said, using the political term for harsh rhetoric. "After four years of George Bush, we just need honesty for a change."

— Being open to reducing the rate of Medicare growth. "In one breath, Howard Dean says he would never cut Medicare. In the next breath, it's on the table for budget cuts."

— Opposing the assault weapons ban as Vermont's governor, but supporting it in the liberal-leaning presidential primaries.

"I've come to realize that Howard Dean isn't shooting from the hip. That's just making excuses for him," Gephardt said. "Howard Dean knows exactly what he's saying when he says it. And if you think he's contradicting himself, well, as far as he's concerned, that's your problem and not his. Democrats deserve a lot better."