How Sanders' Prolonged Campaign Could Both Help and Hurt Clinton

— -- Even though Sen. Bernie Sanders' decision to stay in the Democratic presidential race has irked some Hillary Clinton supporters, there are ways that his candidacy may help his rival and the party on the whole in the long run.

One of the biggest advantages has been a jump in the enthusiasm among the political base, experts say, and the impact that is having at the polls as more and more people are registering to vote for the first time or switching their voter registrations to vote in the Democratic primaries.

Sanders' team points to increased voter registration as being a clear example of how his candidacy is good for the party on the whole.

"It's my understanding that so far this year over 900,000 people have registered to vote or changed their registration in California. Much of it is attributable to Bernie," Sanders' senior adviser Tad Devine told ABC News.

Vince Vasquez, a senior policy analyst at the National University System Institute for Policy Research, told ABC News that state experts predict that there will be upwards of one million new registered voters in California this year, but that figure comes from all three parties.

Devine argues that the new voters still help Democrats significantly because of California's primary rules.

"The combination of massive voter registration and high Democratic turnout -- since there is a contest on our side and independents can vote in the Democratic primary but not in the Republican primary -- could lead to enormous advantage for Democrats in the fall in the biggest state," Devine said.

Beyond the presidential primary, having a strong Democratic turnout in the California primary could lead to more Democrats in Congress, Sanders campaign spokesman Michael Briggs told ABC.

"There's also a quirk in California election law these days where in the primary, the top two vote-getters go on to the general election. So you could have situations where him, Sen. Sanders, being in the race and creating that kind of excitement helps with Democratic turnout so that you get congressional districts where the [No.] 1 and 2 finishers are both Democrats and that will help the party in the long run," Briggs said.

The drawbacks of a prolonged primary are not without consideration, however.

Hans Noel, an associate professor at Georgetown University, says that Sanders' arguments, and those of his supporters, against Clinton that paint her as "basically a Republican" will have a lasting impact.

"One thing we know from political science is that it is very hard to correct people’s misperceptions, so now that more people believe those things, it’s going to be hard to undo them," Noel told ABC News.

James Campbell, a professor of political science at the University at Buffalo who has written a book about political polarization, said that the attacks from Sanders have hurt Clinton and her case that she is the strongest candidate for president.

"It has exposed Clinton's vulnerabilities. She has not come out of this with the image of a strong or invincible candidate," Campbell said.

He also noted that many Sanders supporters won't be satisfied with Clinton, should she secure the Democratic nomination.

"Many of these will be disappointed when Clinton is awarded the nomination after Sanders won so many caucuses and primaries and has energized the base," Campbell said.