AMERICAN leaders should take care not to savage their political system as they did the Indians and the environment they found in the New World.This is Thanksgiving time here. But thanks are hard to come by. Instead of dwelling on the vision and continuities of the New World experience, our mistakes and lessons therefrom, we hear from Washington much moaning and complaint. George Bush's popularity erodes as the economy stagnates. White House Chief of Staff John Sununu should take the hint, backbiters say, and step aside, taking the blame with him. President Bush has no domestic vision, so bring in Housing Secretary Jack Kemp, an indefatigable conservative thinker and optimist, as policy czar. Meanwhile, Congress, too, is in the dumps. Nobody loves Congress. Idealistic young members like Ohio's Rep. Dennis Eckert want out: too many family decisions made on the office telephone instead of at the breakfast table, 90 airplane trips a year, elusive accomplishments, Eckert says. Marathon fund-raising and negative ads make elective politics a mean business. What do you do when reelection no longer feels like success? From the discussion, the United States political system would appear to be at the verge of collective burnout. Washington should guard against the exploitative side of the American adventure. The Indian saga in America cannot be rewritten; at least it could be better understood. The resources of fish, land, prairie (where not ruined by agriculture), industry, and recreation, should be more highly prized and protected. So with politics. There is nothing inherently amiss in the US political system. True, Congress has gotten too complicated: Each budget item is considered some eight times before finally being decided, for example. A joint committee will be looking into ways to make the Congress more efficient in the coming year. This could help. Term limitations would not help. Running down Congress and against Congress, by the president or by members of Congress itself, does not help: All must work within the political system they bad-mouth. Bush needs to stabilize his ship. He comes from the mercantilist, trade-centered tradition of New World development. He appears to be more the Virginia Colony type than the Plymouth Colony type - an economic expansionist rather than an explorer of religious and intellectual freedom. We know the hyperactive George Bush. We do not know the reflective George Bush. What's he thinking about? Does he read? Speeding in his cigarette boat, does he think about the waters that will be here 10,000 years after he's gone? Mr. Sununu helped Bush win the New Hampshire primary three years ago after a bumpy start in Iowa. To dump Sununu would not help in next February's repeat contest. But if this were done, Bush could turn to a Gen. Colin Powell as chief of staff, or perhaps even Defense Secretary Richard Cheney. Secretary of State James Baker, his ace political adviser, will be around, particularly if the Middle East peace talks are held in Washington. The more of his foreign policy activities Bush can draw to Washington, t he better. So the current White House "crisis" can effectively be put behind him. To have the president on the road for public appearances, the current plan, to shore up his domestic policy image would be cynical and self-defeating. Scurrying about will not tell the public where, as a leader, he is heading. What's the president thankful for? What are the continuing values that will help America renew itself? If he held a Thanksgiving dinner on the White House lawn, whom would he invite? Congress? Business leaders? Schoolchildren? The homeless? The new immigrants? Who are his friends? Behind the public grumbling is a sensible political question: Whose America is it, anyway? American history has been no picnic. The Virginia colony lost 6,000 of its first 8,000 settlers. Plymouth hardly did better. But tough times are the moment to take our bearings with a round of thanks.