COMMENTARY ON THE INCOMING ADMINISTRATION : Onetime White House Insiders Share Benefits of Experience : Clinton cannot count on a cozy relationship with Congress, which is intent on shifting the balance of power toward itself.

Combine the youthful and brainy policy work with the “same-party-end-the-gridlock” Congress and you have the Washington dream team. Not.

With few exceptions over the last three decades, Congress has not much liked the occupant of the big house at the other end of Pennsylvania Avenue. And this central dynamic of modern government will be the principal hurdle as Bill Clinton attempts to enact his agenda.

Congress has grown in size, in arrogance, and, worse, in its single-mindedness to shift the balance of power toward itself.

* A pliant, post-Kennedy-assassination Congress turned on Lyndon B. Johnson over the war in Vietnam.

* No honeymoon for Richard M. Nixon. He continued the war in Vietnam and persevered to a peace accord, and this fueled congressional resentment made worse by his 1972 drubbing of liberal hero George S. McGovern.

* President Gerald R. Ford was treated as a coequal by his former congressional colleagues, while President Jimmy Carter’s contempt for the jealous satraps who ruled their Capitol Hill kingdoms mired him quickly in the obstacles of their arcane ways.

* Ronald Reagan made use of narrow windows of opportunity--an election mandate for economic change and the nation’s embrace of him after surviving a bullet wound--to achieve important results. But it was fixed bayonets most of the time.

* Poor President George Bush. From the beginning, the Democrats were determined that he should not succeed--even after the end of the Cold War and a brilliant Persian Gulf victory--so that they could reclaim the presidency.

That history of a generation gives the new President a Congress muscle-bound with the accretion of the powers it grabbed in the post-Vietnam, post-Watergate era.

Congress has become self-indulged and self-important. There, committee chairmen rule. The immunity it grants itself from executive-branch pressures (though not from its own pet special interests) will bedevil Clinton.

Health care reform, economic change, the conduct of foreign policy and a renewal of public confidence will hang on Clinton’s ability to overcome what has become the preeminent natural enemy of the American presidency.

We’ll await the outcome. But some advice to the man from Arkansas: Don’t expect the Washington crowd to cut you any slack. One more thing. There’s an old and wise piece of advice for new residents along the Potomac: With apologies to Socks, if you want a friend, buy yourself a dog.