TURMOIL IN SOVIET REPUBLICS : White House Backs Troop Deployment : Soviet Union: The U.S. recognizes the need to restore order in the restive republics.

The Bush Administration on Tuesday offered a green light to Soviet President Mikhail S. Gorbachev’s dispatch of troops to the rebellious republics of Azerbaijan and Armenia, a move that Administration officials called the largest single Soviet troop deployment since the beginning of the Afghanistan invasion more than a decade ago.

“We understand the need to establish order where order has broken down,” White House Press Secretary Marlin Fitzwater said. “We recognize the right of any state to ensure the safety of its citizens.”

The White House statements mark the third time in roughly six weeks that the United States has endorsed Soviet use of force--a clear indication of how much official American perceptions of Soviet actions have changed in the past year.

In late November, just before the Malta summit, Secretary of State James A. Baker III said the United States could support the use of Soviet force in restive republics if violence broke out there. And last month, Baker said the United States would not object if the Soviets sent troops to Romania to aid in ousting the late dictator Nicolae Ceausescu.

In the past, American officials concede, the U.S. government would routinely object to any use of Soviet power to put down internal unrest or to intervene in the affairs of neighbors.

Administration officials, noting reports that warring forces in the two republics have equiped themselves with armored personnel carriers, helicopters and weapons taken from military stores, say the situation there has become critical.

“It’s partisan warfare,” an official said. “It’s really bad today. Gorbachev may be able to constrain it, but the longer it goes on, the worse the consequences.”

A second official added: “It’s pretty grim. When these guys kill each other, it’s serious stuff.”

The Administration has been monitoring signs of the Soviet force buildup since Friday, when White House officials were briefed on indications that Gorbachev planned to use troops to quell the fighting. Since then, however, there have been no direct contacts between high-ranking U.S. and Soviet officials about the unrest.

Administration officials appear confident that in the wake of last month’s Malta summit, the two nations have worked out a general understanding about what situations justify the use of force.

Until recently, U.S. officials refrained from supporting any use of Soviet military power to put down unrest, seeing any disturbances there as a form of welcome rebellion against the Communist government. Baker offered a clear break from that policy during a White House press conference on Nov. 29.

Asked whether some circumstances would justify a Soviet “crackdown against people in his own country,” Baker replied: “It depends what you mean by ‘crackdown.’ Suppose you have Azerbaijanis and Armenians actively fighting each other, killing each other. Would it be inappropriate for the central authority to try to restore peace, whether through martial law or otherwise?

“In my view,” Baker said, “that’s far different than using force to suppress peaceful dissent.”

Now that Baker’s hypothetical situation has turned real, the Administration has quickly rallied to Gorbachev’s support. But Administration officials recognize that the deployment of several thousand troops to the region is what one analyst called a “calculated risk” for Gorbachev.

Backlash Anticipated

Until now, the fighting between Armenians and Azerbaijanis has reflected deep hatred between the two groups but much less animosity toward the Russians who control the central government. Sending troops could inflame anti-Russian feeling, U.S. officials say, and cause a backlash of sympathy for the Azerbaijanis, an Islamic ethnic group, in the Soviet Union’s other Muslim republics.

Also, the analysts noted, quelling the fighting may not prove easy. “The Azeri National Front is in an excellent position to wage warfare, and so are the Armenians,” an official said.

Gorbachev needs to take the risk to demonstrate to his own critics within the Communist Party that he will not allow the Soviet Union to dissolve, U.S. analysts believe. And he must show other nationalist forces that there are limits to Moscow’s patience.

“He’s sending two messages,” said one official. “To his own critics, he’s saying, ‘I’m in charge.’ To the republics, he’s sending a message that there are limits on perestroika ,” his sweeping program of political and economic reform.