On a scheduled 17-day vacation following his summit triumph, George Shultz managed to find time to threaten resignation over two items high on his personal agenda.

One item was congressional efforts to keep the Soviets from moving into their new quarters here until the new U.S. Embassy in Moscow is cleansed of communist bugs. Shultz won that one; it was stripped from the big money bill at 2 a.m. Tuesday morning, when few were looking. The other item was polygraph testing imposed by Congress on the State Department's security agents. He lost that one; it stayed in the bill.

The secretary of state fought both congressional edicts like a mother tiger protecting her cubs. If they passed, he warned Chairman Dante B. Fascell of the House Foreign Affairs Committee, he might resign. He told Rep. Daniel A. Mica, a sponsor of the embassy ban, that he considered it a ''personal affront.''

The surprise, post-midnight House waiver of the Soviet Embassy ban showed that when Shultz commits himself to a fight, he often wins. But it also shows what George Shultz really cares about: first, anything related to U.S.-Soviet de'tente, be it glamorous summits and arms control treaties or facilitating Soviet housekeeping in Washington; second, anything furthering State's bureaucracy, be it replacing political appointees with Foreign Service officers as ambassadors or shielding security agents (whose job is to safeguard state secrets) from lie detector tests.

His resignation talk this week over what he cares about sounded a familiar note. He threatened to quit in December 1985 when lie detector tests for all State employees, not just security agents, were suggested. Other matters often have been sloughed off during Shultz's successful five-year tour as diplomat.

Although opposed when originally asked about selling U.S. arms to Iran, he never threatened to resign over what he suspected would become one of the most humiliating chapters in U.S. diplomatic history.

In the current crisis over Israeli use of live ammunition to put down rioting by stateless Palestinians, the secretary has stayed aloof.

He showed no interest in meeting an important Arab ambassador who wanted to plead that U.S. interests in the Mideast were being savaged by Israel's conduct. This envoy and others seeking to persuade the United States to pressure Israel into an international conference on the West Bank were denied access to the secretary.

Although Shultz has displayed commendable loyalty in protecting from Congress Assistant Secretary Elliott Abrams and other officials central to Nicaraguan policy, he kept clear of vicious infighting over the new $10 million contra aid package. National security adviser Colin Powell and White House lobbyist Will Ball get the credit. Leading the contra funding charge would have threatened cozy relations Shultz has cultivated with liberal Democrats on Capitol Hill.

As for the West Bank crisis, it is felt by some in the State Department that Shultz wrongly calculates that his political loss would be unacceptable if he took on the Israeli lobby and pressured Israel to stop killing and start negotiating. ''The secretary does not understand that most Jewish leaders would welcome restrained but real American pressure on Israel,'' a State official told us.