Initial political reaction to President Carter's televised address last night was supportive, though the acting minority leader of the Senate called the president's program of sanctions against the Soviet Union "premature."

Politicians of both parties, including several presidential candidates, said they endorsed Carter's moves.

The usually combative John Connally was surprisingly supportive of the president's address. He said he wholeheartedly approved of the grain embargo and the president's call for the use of American grain in the production of gasohol.

Of the embargo, the GOP presidential candidate said, "It deprives grain from the Soviet Union. They're having trouble meeting the needs of their country. If they're denied this wheat, they're going to have to get it from somewhere else." He said he hopes, however, that Carter has firm assurances from the governments of Canada and other grain-exporting countries that they will not sell additional wheat to the Soviets.

Rep. Jim Wright (D-Tex.), the House majority leader, said he had "no doubt whatever that Congress will support the President entirely in any legislation required to carry out this country's firm and measured response to the Soviet aggression."

Sen. Ted Stevens (R-Alaska), the acting minority leader, said he thought the president's moves were premature because they were made without giving the international community a chance to act through the United Nations. "I don't criticize the actions he has taken," Stevens said, but he added that Carter could have given the Islamic world an opportunity to learn that "the United Nations could help solve its problems."

Stevens said he gave this advice to the White House Friday afternoon when an aide to Carter asked for his views on moves against the Soviets.

The Senate majority leader, Robert C. Byrd (D-W. Va.), called Carter's actions "appropriate at this time." He urged America's allies to support the president's decisions, and said he hoped "the so-called nonaligned and Third World countries would be shocked into seeing the Soviet Union through other than rose-colored glasses."

Rep. John B. Anderson of Illinois, a moderate Republican presidential challenger, warmly endorsed Carter's moves.

"Particularly in the area of high technology and food grains," Anderson said, "I think the action taken will send a clear signal to the Soviet Union of our disapproval of their adventurism in Southwest Asia."

Sen. Frank Church (D-Idaho), chairman of the Foreign Relations Committee, who is in a tough reelection campaign, said from Idaho that he endorsed Carter's decisions. Church said he especially approved of plans to protect American farmers who will lose sales to the Soviet Union, and he applauded the idea of converting some of the grain previously intended for the Soviet market to gasohol.

F. Don Miller, executive director of the U.S. Olympic Committee, expressed cautious satisfaction that Carter had kept "our options open" regarding U.S. participation in the Moscow Olympiad next summer.

Miller said an American boycott "would be the death of the modern Olympic games," and urged the administration not to use the Olympics "as a vehicle for international politics."

Sen Charles H. Percy (Ill.), second-ranking Republican on the Foreign Relations Committee, supported Carter's moves. "The Soviets must be made to pay a high price for their bald-faced aggression in Afghanistan," Percy said.

Sen. David Pryor (D-Ark.), a freshman, said: "Thank God we're going to do something -- it may be wrong, but at least it's something. The decision on grain is proper -- I just wish he'd gone all the way with it. I would have preferred that none of the grain go to the Soviet Union."

Sen. George McGovern (D-S.D.) said he approved of firm action against the Soviets, but added, "I am skeptical about a grain embargo by the United States. It may hurt the American farmer more than the Russians. The Russians can reduce their livestock feeding and tighten their belts, but the loss of this huge market will cost American farmers and taxpayers painfully."

And Sen. Roger W. Jepsen (R-Iowa) said: "When the truth is known, the embargo is going to hurt Iowa farmers more than it is going to hurt Russians. Because of Iowa's heavy exporting in grains and farm machinery, Iowa farmers and industrial people will be the whipping boys of this embargo."

Senate Minority Leader Howard H. Baker Jr. (R-Tenn.), or landing in Des Moines tonight, said he would support Carter on the idea of resuming military aid to Pakistan, but he attacked the president's partial embargo on grain shipments to the Soviet Union. Baker called the embargo a mistake.

Agriculture embargoes, he said, "almost never are an effective tool of foreign policy. You always starve the wrong people . . . . I don't think the grain embargo will discommode a single person in the Kremlin."

Baker said he also opposed the president's proposed government purchase and export subsidy program, but added that Carter's proposals may have been "the only options he thought he had left."

"Iran and Afghanistan are part of a failed foreign policy," Baker said. "They are a commentary on the mismanagement of American foreign policy in the last 3 1/2 years."