In my home state, split votes twice allowed the Republican Paul LePage to win election to governor. If we ignore the math and the populist anger, and alienate Sanders supporters, we could end up waking to a nasty election hangover on Nov. 9.

To build unity, Democrats must re-establish trust with the base of the party. Platform changes, if only symbolic, are a big part of that. Mr. Sanders helped devise the most progressive party platform in United States history, winning concessions that include support for a $15 minimum wage and an expansion of Social Security. What remains is to ensure that grass-roots Democrats people can express their voice in the party’s nominating process for president.

That is why I recently submitted an amendment to the party’s rules committee that would eliminate superdelegates. It would leave in place the current system of pledged delegates, who are elected in proportion to each state’s popular vote. Party bigwigs can have a privileged place at the national convention, but they should not have privileged votes.

Getting rid of the superdelegate system will not mean the end of our efforts to make the party fully democratic, but it would lay a firm foundation on which to build a stronger, more progressive vision for our country. More important, rank-and-file Democrats will get back their voices — and their confidence that their votes count.

The rules committee should send the proposal to the convention floor in Philadelphia and recommend that the convention delegates support it. To borrow the words of one of that city’s favorite sons, Benjamin Franklin, we have a republic — if we can keep it.