One result of Israel's push into Lebanon in recent days has been a revving up of the President's crisis management organization, now called the Special Situation Group.
The group has assembled four times since June 5. This is as many times as it met in all the previous months since Mr. Reagan announced its formation early in his administration.
Vice-President George Bush chairs these sessions. In an interview he explained the group's way of working. ''We really do not manage crises,'' Mr. Bush said. ''What we do, infrequently, in the absence of the President, is pull together the highest-level policymakers at the national-security establishment and sort out matters, or try to flesh them out before they are presented to the President.''
''Or,'' he added, ''we do follow-up work after the President has met with the national-security apparatus.''
''It's not a thing,'' he said, ''that every time there is a hot spot, I jump into the chair down there and try to formulate policy. It was never conceived to be that.''
Participating in recent Special Situation Group (SSG) sessions on the Mideast were: Vice-President Bush; Walter J. Stoessel, deputy secretary of state, sitting in for Secretary of State Alexander M. Haig Jr.; Robert C. McFarlane, deputy assistant to the President for national-security affairs, sitting in for National Security Adviser William P. Clark; Gen. David C. Jones, chairman of the Joint Chiefs of Staff; Secretary of Defense Caspar W. Weinberger; Central Intelligence Director William J. Casey; and Jeane J. Kirkpatrick, US representative to the United Nations.
Despite the acceleration of SSG meetings since Israel moved into Lebanon, the vice-president says he believes that the strong coordinating role now played by Mr. Clark will mean less of a need, over the long run, to call together this group.
In his day-to-day activity, Mr. Clark deals frequently and thoroughly with the same people who make up the SSG.
''The way Clark runs the National Security Council,'' Mr. Bush says, ''and his proximity to the President, will mean there will be less of a requirement for a lot of SSG meetings.''