A FUNNY thing happens when elections really matter: Voters go to the polls in droves. Such was the case during the long battle between Barack Obama and Hillary Clinton, which produced record turnout in Democratic contests from coast to coast.

The dynamic will change in November, when perhaps a dozen states will be battlegrounds in the presidential race. And that's why the state Legislature should pass the National Popular Vote bill, which commits a state to throwing its electoral votes to whoever gets the most votes nationwide. While Senate President Therese Murray and House Speaker Salvatore DiMasi both support the bill, it may not pass before the end of the legislative session next month.

The measure would only take effect if adopted by states representing a majority of the Electoral College, and proponents aren't likely to reach that threshold this year. In the future, though, the plan would eliminate the most obvious flaw in the current system: that the candidate with the most votes can still lose, as Al Gore did in 2000. A major side benefit is that the plan would widen future presidential races to all 50 states. While election turnout depends heavily on a state's laws, the dearth of campaigning in sure states has its consequences. Four years ago, turnout among voting-age adults was lowest in California and Hawaii, where John Kerry won easily. Turnout was highest in Minnesota, where Kerry won with only 51 percent, and Wisconsin, where George W. Bush barely squeaked past 50 percent.

Under the National Popular Vote plan, a vote in deep-blue Massachusetts or deep-red Utah would count as much as a vote in Michigan or Ohio. Candidates would feel less obliged to make policy zigzags to appease swing-state special interests. Anti-Castro hardliners in Florida and steel interests in Pennsylvania might not enjoy the same outsized influence. But for voters, the benefits would be enormous.