U.S. Rep. John Kline surprised even keen Minnesota political observers with his announcement Thursday that he would not seek an eighth term representing the south-suburban Second District. But House insiders may have been less surprised. They’ve been noting a pattern of retirements among Republicans who are compelled by a caucus rotation rule to surrender their gavels after six years in committee leadership chairs. Three Republicans in that situation ended their service in 2014.

The impending end of his leadership of the House Committee on Education and the Workforce seems to have weighed heavily in Kline’s decision, judging from his comments to Minnesota reporters in a conference-call discussion of his plan to leave Congress at the end of his current term. Kline said he still relishes his committee assignment. He’s eager for 16 more months of work on a policy to replace No Child Left Behind and on improved higher education accessibility, he said.

But “I cannot continue as chairman past this Congress,” he said when asked why has chosen not to run again. “That’s part of it,” he conceded.

Kline added that he considers the periodic rotation of committee chairmanships “a good thing to do” in principle. Without such a rule, some chairs acquire “power way out of proportion.” But he voiced ambivalence, too. “You don’t like the idea of stepping aside.”

We aren’t as sanguine about the committee rotation rule. It takes years to acquire the deep knowledge that’s needed to set sound national policies — not to mention the seniority needed to rally national support for local needs. For example, Kline has recently emerged as an important advocate for underfunded Bureau of Indian Education schools, including Bug-O-Nay-Ge-Shig School in Minnesota. Demoting someone who has acquired his expertise after only six years simply because “time’s up” squanders a valuable lawmaking asset.

As one who will turn 68 on Sunday, Kline said he considered himself “not that old, but not that young either. If there are other opportunities, other challenges out there for me, this is a good time to step aside. I can move on to other things.” After a lifetime of public service that included 25 years in the Marine Corps, we have no doubt that those “other things” will benefit the common good. Kline has earned Minnesotans’ thanks and good wishes.