At this time of year, there's only one story in New England: foliage. But those of us who lack the literary skill to do justice to the colors are forced to fall back on another product in which Maine excels: politics.

For a small state with barely more than a million people, it has a rare knack for insinuating itself into the center of events. Former Maine senators Margaret Chase Smith and Edmund S. Muskie are happily still around to remind us of the pivotal roles they played in both parties' affairs from the 1950s to 1980. One recalls Smith's "declaration of conscience" against Joe McCarthy and Muskie's leadership on the budget in the Senate and stewardship of foreign policy at the end of the Carter administration.

Today's Maine senators, Republican Bill Cohen and Democrat George Mitchell, are powerhouses on the Armed Services and Finance committees, respectively. Mitchell doubles as the man in charge of the Democrats' effort to regain the Senate majority in 1986, and Cohen moonlights as the most prominent practicing poet-novelist in the Senate.

Because he summers in Kennebunkport, Maine regards Vice President George Bush as its entry in the 1988 presidential sweepstakes. But because its delegate caucuses come almost as early in the nominating calendar as the New Hampshire primary, it is also the center of attention for ambitious Democrats. New York Gov. Mario Cuomo was washed out of a scheduled Maine appearance last month by Hurricane Gloria, and Sen. Gary Hart of Colorado and Rep. Richard Gephardt of Missouri, both running hard for 1988, will be here this coming weekend for the Democratic state convention.

In 1986, too, Maine will present a microcosm of the national political battle, as Republicans try to move into a stronger position in state government and Democrats seek to regain their hammerlock on control of Congress.

The first step in the drama occurred on Sept. 26 when second-term Rep. John R. (Jock) McKernan Jr. (R) announced he would run for governor. The second step will come later this month when -- from all indications -- retiring two-term Gov. Joseph E. Brennan (D) will declare himself a candidate for the House seat McKernan is vacating. McKernan's race is one of the central pieces in the national GOP effort to erase the 2-1 Democratic advantage in governorships, and thereby extend the "Reagan Revolution" beyond Washington and into state government.

Brennan has been ardently courted by national Democratic leaders, not only as a man who can help bolster the House majority in 1987, but as someone who might have the credibility and experience to challenge Cohen when he comes up for reelection again in 1990.

Both enterprises are surrounded by uncertainty at this point. It's the kind of drama that promises to make 1986 an unusually intriguing nonpresidential year in politics.

In Brennan's case, the major question mark is his willingness to run. The 50-year-old Portland lawyer has spent most of the last two decades in state government and enjoys broad popularity as the governor whose tenure has seen rapid economic growth and major education improvements.

Generally speaking, a governor who has gone to the bother of researching the number of other governors who moved to the House of Representatives, as Brennan has done, can be assumed to be contemplating such a move himself. He even volunteers in a conversation that he really likes Washington as a place to live and has a couple of bills in mind that he'd like to promote.

A visit with Brennan left me thinking he would attempt the unusual jump from senior governor to junior member of the House. But others who know him say they tink he has real reluctance to uproot himself, and so the state awaits his own word, soon forthcoming.

If Brennan runs for the vacated seat, even Republicans concede he will be the favorite. McKernan, along with his colleague, Republican Rep. Olympia Snowe, is regarded as a bright hope for the GOP future, but he has many hurdles to clear before he is governor. It is going to be interest- ing to see how much help the 37- year-old Portlander gets from the Reagan White House in his quest. McKernan, like most Maine Republicans, is a moderate who has split from Reagan on some environmental, trade, foreign policy and fiscal issues. That has earned him the declared opposition in the primary of Porter Leighton, an early Reagan supporter and Reagan appointee to a federal regional post in Boston.

If, as expected, McKernan survives the primary, he will face not only the survivor of the Democratic nomination contest but the announced independent candidacy of Sherry Huber. She is a welthy Republican disappointed in her previous efforts to win a nomination.

In short, the Republicans here are giving up something secure -- McKernan's hold on his House seat -- and gambling on something risky, with much of the gamble involving the question of GOP unity or fragmentation. That's the kind of risk they have to take if they are ever going to be the majority party. And it's the kind of bet that is going to make 1986 so interesting in so many states. It's especially nice when you get all this -- and foliage too.