POLITICAL talk today revolves around ''gridlock'' in Washington and the coming ''train wreck'' in which the federal government would shut down if Congress and President Clinton don't agree on a budget. The public is fed up, we're told, angry with Democrats and Republicans, mad that nothing gets done. Congress is too involved in ''playing politics.'' ''Special interests'' block legislation that the public clearly favors. Wait a minute. Yes, it takes a long time and a lot of effort to change the federal government. But isn't that precisely what the Founding Fathers had in mind? They purposely built a governmental system that was cumbersome and required a broad consensus for change. Maybe instead of decrying that, we ought to take a minute to appreciate its benefits. America is not a monolith. It is not a traditional nation-state like France, England, or Japan, in which one fairly homogeneous group with a tightly defined nationality lives in a relatively compact territory. The US has deep regional, ethnic, religious, and social divides. What unites Americans is the shared ideals set forth in the Constitution - and a sense that fairness comes from the incessant bargaining and compromise inherent in the federal system uniting the diverse nation's diverse parts. That Constitution sets up a system in which the majority cannot run roughshod over the rights of minorities. A lot of people representing a lot of interests must agree before a bill becomes law. To amend the Constitution itself requires the consent of no less than 75 percent of the states. That's not a formula for quick changes. It's meant to promote careful consideration of legislation, not laws rammed through in the heat of the moment. Consider the alternative. A parliamentary system may be more efficient, but it also makes it far easier to force through changes the public doesn't want. In Canada or Britain, the prime minister and a small group of Cabinet officials run the show, while most members just show up to vote for or against. Had that been the case here during consideration of President Clinton's health-care proposals last year, they would have been law for about a year now. Those who think that would be a good thing should consider how they would react to conservative Republicans wielding that much power after the '96 elections. Our federal system is slow and often frustrating. That's not going to change, regardless of who wins the next elections, because the government was designed to be that way. Change will come, but only when enough Americans - and their elected representatives - are ready.