The Senate Armed Services voted 16 to 1 this week to give President Reagan almost everything he has asked for in the way of new weapons. The dissenter was Democratic Sen. Carl Levin, a former Detroit councilman who believes Reagan does not know what he is talking about and the Pentagon does not know what it is doing.

Given that conviction, Levin said in an interview, voting against the Pentagon's $180.2 billion procurement bill was the only logical thing to do. "It was too big and had too many items that were indefensible, such as the B1 bomber, the two aircraft carriers, F15 fighters for air defense," he said. "It was a very sound vote. I had no hesitation to cast it . . . . "

Of the political risks of bucking the anything-for-defense tide, he said: "Some people will try to paint the vote as being soft on defense. But most people understand that the defense budget should not be a sacred cow.

"I'm for a strong national defense. I favored a 3 percent real increase to keep our commitment to NATO. And I think our NATO allies ought to keep that commitment" to increase defense spending, after allowing for inflation, by 3 percent a year.

But in calling for a real spending increase of 9 percent from fiscal 1982 to fiscal 1983, Reagan and the Pentagon are ignoring the economic threat facing the United States, Levin contended. This threat is "more imminent and serious" than the military one, he said.

"I say that without downgrading the need for a strong defense. But the economic insecurity of this country is something now that must have a much higher priority. The deficit must be decreased dramatically, and you have to reduce the increase in the defense budget to do it. If the economic situation continues to worsen in this country, I would reconsider even the 3 percent commitment.

"Every time we waste defense dollars we weaken our defense," Levin continued, citing as an example the B1 bomber, which he described as "a piece of second-rate military equipment because it won't be able to penetrate Russian airspace for more than a few years."

Another waste of money, he said, is buying the MX missile without knowing where to put it. "I haven't seen an intelligent way to base it yet," he said. "My inclination is to kill the MX outright. Not only for that reason but also because I don't buy the assumption that the Soviets can eliminate the 1,000 Minuteman missiles we already have in a coordinated strike over a polar axis they have never tested, and not expect, and indeed receive, a severe retaliatory blow.

"I think the president was wrong" when he said the United States was inferior to the Soviet Union in nuclear weaponry, Levin said. "I don't think the president knows what he's talking about in that area. There's two non sequiturs he used to prove it."

(Reagan said that "on balance, the Soviet Union does have a definite margin of superiority, enough so that there is risk, and there is what I have called . . . several times a window of vulnerability . . . . The Soviets' great edge is one in which they could absorb our retaliatory blow and hit us again." Asked whether he thought "a nuclear war would be winnable or even survivable, and under what conditions," Reagan replied: "I just have to say that I don't think there could be any winners; everybody would be a loser if there's a nuclear war.")

"Saying the Soviets could respond to our response is a non sequitur," Levin said, "because that doesn't mean we're weaker. He doesn't say whether we could, in turn, respond to their response. To say that the Soviets could respond, although we retaliated, does not prove in any way a position of nuclear inferiority, any more than the fact that we could respond to their attack proves that we're nuclear superior, which we're not.

"The other non sequitur," Levin said, was Reagan's statement that neither side could win a nuclear war "at the same time he is saying the Soviets are superior in nuclear weaponry."

Levin charged that Reagan is so captivated by his campaign rhetoric about U.S. military inferiority that the American people are now hearing contradictory statements from the president and the nation's top military officer, Gen. David C. Jones. The joint chiefs' chairman has said he would not trade U.S. military might for that of the Soviets.

The grass-roots demand for a halt to the nuclear weapons buildup is new proof, Levin contended, that the American people are ahead of the politicians in realizing that more nuclear weapons would not bring more strength. "There is a growing sentiment of frustration with political leadership," Levin said. "We're being given a message. The people want to see some progress on nuclear arms control.

"The people are right," said the 47-year-old Levin in contending that his lone vote against the Pentagon procurement bill is out of step with the committee but not with the growing public feeling that Reagan and the Pentagon are indulging themselves in overkill in structuring the defense budget. He vowed to continue his uphill fight on the Senate floor, but acknowledged he probably will not be on the winning side there until next year.