John Behan, a Republican state assemblyman in New York and Vietnam veteran who lost both legs in the war, said yesterday that he has been nominated to head the Veterans Administration. Behan, 36, a former Marine, said he understood a formal announcement is to be made today.

Behan has said he would eliminate unnecessary bureaucracy in the agency while improving service to Vietnam veterans, especially those exposed to the defoliant Agent Orange, suspected of causing lingering medical problems.

If Behan is confirmed by the Senate, he will succeed another Vietnam veteran, Max Cleland, as head of the agency.

A second candidate has dropped out of the race for Democratic National Committee chairman, putting the job even more firmly into the bag for Californian Charles Manatt.

Patrick Cunningham of New York City, in a Mailgram to national committee members, acknowledged that he didn't have the votes to win and pledged his support to Manatt.

Missourian Charles Curry dropped out earlier this week and endorsed Manatt. The Mailgram announcing Curry's withdrawal, however, was a joint missive with Manatt, who swapped favors by announcing his endorsement of Curry for DNC treasurer.

That leaves only Joseph Crangle of Buffalo as a challenger to Manatt, and Crangle reportedly has no intention of getting out.Energy Secretary James Edwards, looking for advice on energy production, has set up a panel of experts -- most of them corporate energy executives.

Edwards calls his 22-member panel a "citizens task force," and says its guidance "will be invaluable to me as we set forth on the road to increased energy production and economic recovery."

The chairman will be Robert Parker, chairman of Parker Drilling Co. of Tulsa, and other members include Charles Di Bona, president of the American Petroleum Institute; C. John Miller, president of the Independent Petroleum Association of America, and Conoco Chairman Ralph Bailey.

Virginia Gov. John N. Dalton has a seat on the panel, which also will include a utility executive, a member of the League of Woman Voters and an environmentalist: Grant Thompson of the Conservation Foundation.

An expected reorganization of the top jobs at the Justice Department is rolling along. When it's all done, Deputy Attorney General Edward Schmults, who doesn't have much background in criminal law, won't have to deal much with the end of things. He will oversee civil matters, including the antitrust, civil, civil rights, land and tax divisions.

The associate attorney general, expected to be New York lawyer Rudolph Giuliani, will oversee the criminal division, the Drug Enforcement Administration, the Immigration and Naturalization Service, the U.S. attorneys around the country and other matters primarily in the criminal field.

Meanwhile, D. Lowell Jensen, district attorney for Alameda County, Calif., is still the top candidate for assistant attorney general in charge of the criminal division, and Stanford University law professor William Baxter has already set up shop as head of the antitrust division.

There's a reason for putting the cart in front of the horse in the case of Baxter, who is officially working on a consultant basis: the federal judge is the American Telephone & Telegraph Co. antitrust suit has given Justice until March 2 to approve a settlement reached during the Carter administration.

Schmults is not participating in the case because of past ties to AT&T, and it seemed prudent to get someone on board who could deal with the settlement.

Robert Bruce, former general counsel of the Communications Commission, will join Leva, Haves, Symington, Martin & Oppenheimer, where he will develop the firm's communications practice. FCC Chairmen Charles Ferris, who already has announced his resignation, will leave April 11 to enter private practice. . . . Reportedly on the list of candidates for the Office of Adolescent Pregnancy Programs: Marjory Mecklenburg, president of American Citizens Concerned for Life, an antiabortion organization. . . . Another name surfaces for head of the International Communication Agency, and this one means tough competition for Charles Z. Wick, the fellow who's supposed to have the job sewn up. The new name: Walter Cronkite.