ST. PAUL, Minn. (AP) — A longtime Democratic state senator says he won't run for re-election, opening a prime seat for Republicans.

Sen. Leroy Stumpf announced Wednesday that he'll retire from his northwestern Minnesota seat after 2016. The Plummer Democrat has served in the Senate since 1982, after a two-year stint in the House.

His exit is a blow to Senate Democrats aiming to protect their majority in the chamber in November. The massive rural district is more favorable to Republican candidates.

Stumpf, 71, says the time is right to leave the Legislature so he can spend time with his children and grandchildren. He's played a key role in crafting public construction borrowing packages as chair of the Senate's Capital Investment Committee.