Democrats yesterday claimed that they have routed the conservative charge of the once fearsome commandos of the New Right once and for all and have left its leaders and tactics discredited.

Party leaders said that two of the biggest losers in Tuesday's elections were Sen. Jesse Helms (R-N.C.) and John T. (Terry) Dolan, head of the National Conservative Political Action Committee (NCPAC).

Democratic National Chairman Charles T. Manatt said the elections had destroyed "the myth of invincibility of Jesse Helms" and that NCPAC's "credibility is gone and gone for good."

"It is written in the wind that the prince of darkness will be retired in 1984 by a leading Democrat in North Carolina . . . . I'm talking about Jesse Helms and Gov. James B. Hunt," Manatt added.

"NCPAC is on its way out, and I hope its kind of activity will disappear from the political landscape," said Senate Minority Leader Robert C. Byrd (D-W.Va.), a NCPAC target. "It is headed downward, and the Republican Party should realize it is in trouble if it ties its future to the radical right."

The tolling of the death bells probably was premature. NCPAC and Helms' Congressional Club remain powerful political organizations, each capable of raising $10 million for an election. And there was little doubt that they had a major impact in framing the election year dialogue in dozens of states.

"It's foolish to dismiss any organization that can raise $7 million to $10 million in a political cycle," said Victor Kamber, treasurer of ProPAC, a group formed to combat the New Right. "NCPAC and the Congressional Club are going to be around for a long time."

But the election results certainly tarnished the reputations of Helms and Dolan as king-breakers.

NCPAC, which helped defeat four liberal Democratic senators in 1980, missed almost all of its 1982 targets. Of the 17 senators on its original hit list, 16 won reelection. Only Sen. Howard W. Cannon (D-Nev.), plagued with other problems, lost.

Meanwhile, NCPAC critics like Sens. Byrd, Paul S. Sarbanes (D-Md.), John Melcher (D-Mont.), Lloyd Bentsen (D-Tex.), Edward M. Kennedy (D-Mass.), Quentin N. Burdick (D-N.D.) and Lowell P. Weicker Jr. (R-Conn.) all won.

NCPAC similarly failed in a series of House races, notably against Democratic Reps. James C. Wright Jr. of Texas, the House majority leader; James R. Jones of Oklahoma, the House Budget Committee chairman; Bob Edgar of Pennsylvania; Les Aspin of Wisconsin; Stephen L. Neal of North Carolina; Thomas J. Downey of New York, and Philip R. Sharp of Indiana.

Helms' Congressional Club fared almost as poorly. All five candidates the Congressional Club backed in Helms' home state lost.

Hunt, who has his eye on Helms' Senate seat, was credited with mobilizing anti-Helms forces. Hunt put together an awesome organization of government workers, labor, teachers, feminists and party loyalists to battle Helms-backed Republican House candidates.

Hunt also appeared in a series of television ads aired during the week before the election in which he denounced "smear campaigns, vicious commercials, lies and personal attacks" by Congressional Club-backed candidates. "You can vote against that kind of campaign," he added.

After the election, North Carolina Democrats gloated over their victories. Congressman-elect I. T. (Tim) Valentine declared that his Republican opponent, John W. Marin, "should be ashamed of the type of campaign" he waged. "People are fed up with the distortions of the Congressional Club and I'm happy people saw them for what they were," he said.

NCPAC grew famous for similar attacks in 1980 and continued them in 1982. In West Virginia it formed a group called the "Bye-Bye-Byrd Committee," which circulated thousands of copies of a comic book with a cover drawing of the Senate minority leader wearing a turkey costume, and the headline, "Are You Sure He's Really One of Us?" In Maryland, it spent $650,000 on television ads against Sarbanes.

The technique, so successful two years ago, appeared to backfire in state after state. This was largely because Democratic candidates took the offensive against NCPAC, accusing it of distortion and foul play.

New Right leaders blamed their defeats on President Reagan and the White House, claiming the president made a major tactical error in framing the election around economic issues.

"The American people are not looking for someone who says the current problems aren't my fault," said Howard E. Phillips, chairman of the Conservative Caucus. "They wanted someone with a vision of the future."

Dolan said NCPAC has no intention of changing tactics. "I don't think there is any evidence that tough, effective attacks on a candidate's record aren't effective," he said.