POLITICAL life in diverse Prince George's County is alive and full of challenges this year -- some of them putting longtime incumbents o new and valuable tests, others merely pointing up the generally good government that most residents have come to enjoy under their current county executive, Parris N. Glendening. Whatever room for improvement does exist in the local government is on the county council, which could be strengthened by the voters in certain instances. Mr. Glendening is challenged by three candidates: Arthur B. Haynes and Artie L. Polk, neither of whom has attracted noticeable support, and Floyd E. Wilson Jr., a 16-year member of the county council who has been highly critical of Mr. Glendening's leadership but who has offered little in the way of constructive ideas for better government services.

Mr. Wilson has even conceded that some of his criticism of Mr. Glendening has been based on hearsay. His top priorities include working to get rid of School Superintendent John A. Murphy, whom parents and other interested taxpayers across the county credit with improvements in the public schools that have won national attention.

Mr. Glendening, while never famous for electrifying crowds, can take credit for a wide range of improvements in government services during his eight years in office. It takes time for some self-images to change, but residents of Prince George's can take new pride in the quality of life and sophistication of government that have developed under the steady stewardship of Mr. Glendening. His "general plan" for his tenure as county executive has always been grounded in a policy of inclusion -- in particular, concern for the sensitivities of all races. He has said his program for another four years includes greater efforts to reach out to minorities and to establish closer working relationships with the entire membership of the next county delegation to the General Assembly. Mr. Glendening has more than earned another term and is entitled to a strong vote for reelection.

The county council could stand some changes to bring new ideas and approaches to the legislative branches. Some incumbents are unopposed or face marginal opposition in the Democratic primary: Frank Casula in District 1, Hilda Pemberton in District 7 and Sue V. Mills in District 8. In District 2, there is good competition among the Democrats, with three serious challengers seeking to unseat incumbent Anthony Cicoria: Takoma Park Mayor Stephen J. Del Giudice, University Park Mayor Margaret Mallino and former Mount Rainier council member Doyle Niemann. The emphasis of Mr. Niemann on bringing people together across racial, economic and cultural lines has attracted support to match and offers a refreshing new voice for the council.

In District 3, where five Democrats are running, the newest incumbent, Anne MacKinnon, who replaced James Herl this summer when drug troubles led to his resignation -- already has established herself as an engaging, energetic and intelligent force who deserves to retain this seat. District 4 has been treated to a nasty contest between incumbent Richard Castaldi and Bowie Mayor Pro Tem G. Frederick Robinson, a county police official who claims with much hyperbole that the county government is too committed to "uncontrolled growth and development." Mr. Castaldi's interest in regional affairs and transportation issues gives him an edge.

In District 5, four candidates with varied government and/or civic experience are competing for the seat being vacated by Mr. Wilson. Glenarden Mayor James C. Fletcher Jr. offers vision and experience that would serve the district well. District 6 has been diligently served by Jo Ann T. Bell, whose long interest in and service to public education has been most valuable.

In District 9, incumbent F. Kirwan Wineland has done nothing to distinguish himself and didn't even bother to respond to voters' guide questionnaires from newspapers or in most cases to constituent requests for service. His opponent, Robert Isom, offers no previous experience or clues to how he would serve. The winner here will face a Republican, Karen Crownover, which at least will give voters another round to figure this one out.