IN NATURE, EVOLUTION occurs over millions of years. In politics, it is often on a much faster timeline.

In the Massachusetts House of Representatives, about six years seems to be how long it takes for something to evolve so completely that it becomes the mirror opposite of its former self.

So it was that House members found themselves gathering on Thursday to consider new rules that scrap the term limits on the speaker’s post that they approved six years ago. The move gives their current leader, Robert DeLeo, free rein to remain in power as long he and his eminently pliable underlings want him there.

The optics certainly are not good: A speaker who took office after three successive House leaders went down with felony convictions — and who was himself muddied up last year by a corruption trial involving the state Probation Department – now pushing for a rule change to extend his hold on power.

But DeLeo told reporters that despite introducing term limits after taking office as speaker in 2009, his thinking has “evolved” to the point where he thinks they are not a good idea after all. At least not now.

Where you stand, goes the old saying, all depends on where you sit. In this case, it also depends on the circumstances surrounding the place you sit.

Where DeLeo sat six years ago was in a House speaker’s seat freshly vacated by a leader who left under dark cloud and soon found himself under indictment, convicted, and sent to federal prison, where he is today. The term limits that DeLeo pushed for at that time were part of an effort to restore a sense of public trust in a Legislature that seemed to have a conveyor belt running from the speaker’s office to the federal courthouse.

Where DeLeo sits today is in that same seat, but entering what would have otherwise been his final two-year session at the helm of the 160-member House.

DeLeo said with a new governor and new Senate president in place, it is important that the House continue with “the leadership that we have right now, into the future.” Notwithstanding the rumblings about a huge pension boost he could be in line for if proposed raises for legislative leaders go through, DeLeo insisted that the move was less about him than it was something that members felt would be “important for the institution.”

The “institution,” it’s safe to venture, would have survived term limits prescribing a date-certain by which there must be a change in the top House post. Massachusetts state government has proven fairly durable since John Adams first crafted its central tenets in 1780.

The Senate recently went through a transition of power dictated by the 8-year term limit it also operates under. It did make for a somewhat awkward period during which Therese Murray’s successor, Stan Rosenberg, had been chosen but she remained in power. Chaos, however, did not ensue.

Regular change in legislative leadership is healthy, and holding on to power too long has been the downfall of many strong leaders.

Even at the time term limits were adopted, however, DeLeo seemed less than wholehearted in his embrace of the rule. “Is it a symbolic move? Maybe it is,” he told the Boston Globe at the time. “But sometimes symbolic moves can do a great deal in instilling public trust.”

In some ways, he is right about term limits being as much symbolic as substantive. Indeed, it may have been the wrong prescription for a patient nonetheless in need of some strong medicine.

What ails the Legislature comes more from depth of power wielded by its leaders than necessarily from the duration of their reign. The growing centralization of decision-making in both branches has marginalized the role of members, committees, and committee chairs. That tight grip seems as evident in a House speaker’s fifth year as it will probably be in a tenth year.

It’s been part of a steady march away from a body with robust give-and-take and freewheeling debate, and toward one where members too often resemble sheep willingly herded in whatever direction they are led.

So while the scrapping of term limits may be something to lament, maybe even more troubling is the fact that it’s the same lawmakers who marched in lockstep six years ago to impose them who marched into the chamber today to cast them off.

Michael Jonas works with Laura in overseeing CommonWealth Beacon coverage and editing the work of reporters. His own reporting has a particular focus on politics, education, and criminal justice reform.