Among the many lessons to be learned from yesterday’s election in Massachusetts is that politicians should not play games with established law for short-term political advantage.

Like most states, Massachusetts law called for the governor to appoint someone to fill a vacant U.S. Senate seat until the next general election. But in 2004, Republican Mitt Romney was governor of Massachusetts, and Democratic Senator John Kerry was running for president. To prevent Romney from appointing a Republican in the event of a Kerry victory, a bill was submitted to the General Court (as Massachusetts calls its legislature) to strip the governor of this power and require a special election to be held from 145 to 160 days after the seat became vacant. The bill stalled in the legislature, however, until Senator Ted Kennedy personally pushed for its passage. Governor Romney vetoed the bill, but his veto was overridden by the overwhelmingly Democratic legislature.

Kerry, of course, lost the election, so the only result of this maneuvering was to diminish whatever public respect there was for the political establishment in Massachusetts. Then in 2009, Senator Kennedy, dying of cancer, asked that the law be changed again to allow the appointment of an interim senator (by the now Democratic governor, Deval Patrick) until the special election was held. President Obama endorsed the effort to be sure of having the votes in the Senate to push through his health-care legislation.

But by the time the special election was nearing, the wheeling and dealing in the Senate had so disgusted Massachusetts voters that the sacrificial lamb nominated by the Republicans began to look like a political tiger. More wheeling and dealing in the White House to secure union support for a final bill further disgusted the electorate and that — together with a very good campaign by the Republican and a lousy one by the Democrat — was enough to put Scott Brown in the seat held by the Kennedy family (or its surrogates) since before Scott Brown was born.

Had the Massachusetts Democrats and Senator Kennedy simply left the law alone in 2004, this election would not have taken place, and the Democrats’ 60-seat majority in the Senate would still be intact. Had the Massachusetts Democrats, Senator Kennedy, and President Obama left the law alone in 2009, the Senate would have been forced to bargain with Republicans to secure passage of the health-care bill. A bill might have emerged that would have had more public support, and the president and the Democrats might have escaped an epic political disaster.