At key moments in my career, I have forged some remarkable partnerships that I will always cherish: with Republican Sen. Orrin Hatch (Utah) to pass the generic-drug law; with senior House Republicans such as Henry J. Hyde (Ill.), Thomas J. Bliley Jr. (Va.) and Tom Davis (Va.) to pass laws on prenatal care, safe drinking water and pesticide residues on food, and procurement reform; and with Rep. John Dingell (D-Mich.)and President George H.W. Bush on the Clean Air Act and auto standards.

My legislative class of 1974 reformed Congress and brought new energy to the institution. Some say my departure and the retirement of three of my friends and legendary classmates — Rep. George Miller (Calif.) and Sens. Tom Harkin (Iowa) and Max Baucus (Mont.), all Democrats — signal that Congress is irretrievably broken.

I can’t speak for my colleagues, but that’s not how I feel. All my career I’ve wanted more progress more quickly than the process allows, but that has always invigorated me, not discouraged me — and it still does. My reason for leaving is simple: Forty years is a long time, far longer than I ever expected to serve. It’s time for me to give someone else a chance, ideally someone young enough to make the same long-term commitment required for real legislative success.