Republican National Chairman Bill Brock last night accused President Carter and the Democratic Congress of lacking the will to resist "Soviet militarism and imperialism" or protect Israel against threats to its security.

In a strongly worded speech prepared for the Union of Orthodox Jewish Congregations in New York, Brock signaled that his party would attempt to make a major issue of the Carter administration's foreign policy toward the Soviet Union and the Middle East.

Describing the Carter foreign policy as one "in total disarray," the former senator from Tennessee said, "I am afraid that the tragedies of Vietnam and Watergate appear to have paralyzed the will of the president and the president's men, and far too many members of Congress . . . This is the first time, in my memory, that people are beginning to ask whether the president of the United States will in fact lead the forces of the West in defense our most fundamental western values."

Tying together last week's show trial and coviction of Soviet dissident Yuri Oriov and the Senate approval of the President's decision to sell advanced jet fighters to Saudi Arabia, Egypt and Israel, Brock said:

"In the context of the Carter foreign policy, we as Americans have every right to ask what good it does for Russian Jews to risk their lives and the lives of their families in their desire to emigrate to Israel - when there is no Israel with safe and secure borders."

"Soviet militarism and imperialism are on the march again," Brock said. Referring to Soviet-Cuban operations in Africa, he declared, "not since the aftermath of World War II, when the Red Army swept across Eastern Europe and imposed communist rule in its wake, have we seen as blatant and aggressive an effort to extent Russian power across the globe."