Sen. Bernie Sanders praised the Maine Democratic Party on Sunday for adopting a resolution that effectively bans superdelegates.

Beginning in 2020, the amendment, which passed by a voice vote at the party's state convention on Saturday, will tie Maine's five superdelegates to the overall popular vote.

"Maine is trying to make the Democratic Party more democratic," Sanders said in a statement Sunday. "I hope other states follow Maine's example. This is the kind of grassroots democracy that will help the Democratic Party grow and win elections."

Sanders won Maine's March 6 caucuses by a large majority. He earned 64 percent of the vote to Hillary Clinton's 36 percent. Seventeen pledged delegates were awarded to the senator from Vermont. Clinton got eight.

But Clinton walked away with more superdelegates supporting her as Maine superdelegates this year are allowed to support the candidate of their choosing. Three of the superdelegates back Clinton. One is for Sanders. Another is undecided.

Under the new rule, the superdelegates will be allocated proportionally. That system would give Sanders three delegates and Clinton the remaining two.

Sanders has often decried the presence of superdelegates in the Democratic primary process. "Superdelegates in states where either candidate has won landslide victories ought to reflect the decision of the people in their states," Sanders said.

There is momentum for changing the party's rules about superdelegates.

According to a report, the Maine Democratic Party is also petitioning Democratic National Committee members to abolish the superdelegate system at the national level.

As it stands now, Clinton leads Sanders by a wide margin in the delegate count (2,228 delegates to Sanders' 1,454, according to the latest tally), thanks in part to superdelegates support. Clinton has 523 superdelegates backing her, while Sanders has only 39.

In fact, in several states in which Sanders has won the popular vote, Clinton has walked away with more superdelegates, including Minnesota and Colorado. In some states that he won, like in New Hampshire and Washington state, he received no superdelegates.

Clinton needs just 155 more delegates to clinch the nomination. Sanders would need to win about 66 percent of all remaining delegates to catch the former secretary of state, but polls in states yet to hold primaries and caucuses show there is almost no chance of that occuring.

Sanders refuses to concede defeat. Last week he repeated his plan to siphon off superdelegate support from Clinton. He said the Democratic convention in July will be a "contested convention."