BOSTON (Reuters) - The exceptionally negative tone of this year’s race for the White House is souring young Americans, turning some away from the democratic process just as the millennial generation has become as large a potential bloc of voters as the baby boomers.

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Reuters/Ipsos polling shows that Americans aged 18 to 34 are slightly less likely to vote for president this year than their comparably aged peers were in 2012. Some political scientists worry that this election could scar a generation of voters, making them less likely to cast ballots in the future.

Young Americans on the left and right have found reasons to be dissatisfied with their choices this year. Senator Bernie Sanders had an enthusiastic following of younger people before he lost the Democratic primary race to former Secretary of State Hillary Clinton. On the Republican side, some are unwilling to vote for Donald Trump, citing the New York businessman’s sometimes insulting rhetoric on women, minorities and immigrants.

Brandon Epstein, who turned 18 on Monday, had looked forward earlier in the year to casting his first vote for Sanders. Now, the resident of suburban Suffolk County, New York, plans to sit out the vote on Election Day, Nov. 8.

“It’s because of the selection of the candidates. I find them to be not just sub-par, but unusually sub-par,” said Epstein, a student at the Massachusetts Institute of Technology, in Cambridge, Massachusetts. “Something’s gone terribly wrong.”

That sentiment is broadly reflected in poll data that show that young Americans are less enthusiastic about their choices in November than they were four years ago when Democratic President Barack Obama faced a re-election challenge from Republican Mitt Romney.

Some 52.2 percent of respondents aged 18 to 34 told Reuters/Ipsos they were certain or almost certain to vote, compared with 56.1 percent who reported that level of certainty at the same point in 2012.

The national tracking poll was conducted online in English in all 50 states. It included 3,088 people between 18-34 years old who took the survey from Oct. 1 to Oct. 17, and 2,141 18-34 year olds who took the poll on the same days in 2012. It has a credibility interval, a measure of accuracy, of 2 percentage points for both groups.

‘DEEP CYNICISM’

For at least the past half century, young Americans have voted at lower rates than their elders. But this year’s decline in enthusiasm is of particular concern because it comes as the millennial generation - people born from 1981 through 1997 - has become as large a bloc of eligible voters as the baby boomers - born between 1946 and 1964. Each group’s number of eligible voters is approaching 70 million people, according to the Pew Research Center.

“This generation has never trusted the government, Wall Street or the media less,” John Della Volpe, director of polling at Harvard University’s Institute of Politics, said of the millennials. “That’s likely to result in turnout of less than 50 percent and of those who do turn out, there is still a deep cynicism regarding the impact of their vote, whether or not it will make a difference.”

The projected low turnout is a particular concern given recent research showing how important habit is in encouraging voter participation. Put simply, a person who votes in one election is about 10 percent more likely to vote in the next than an eligible voter who opted to stay home, said Alexander Coppock, an assistant professor of political science at Yale University.

“If you extend that logic, if you have an election that fails to turn people on to voting, you’d expect that you wouldn’t get that cumulative effect,” said Coppock, whose article “Is Voting Habit Forming?” was published in this month’s issue of the American Journal for Political Science.

However, not all young voters unhappy with their choices will be staying home. Some plan to cast a ballot anyway, even if only in protest, rather than sitting out.

That group includes Cameron Khansarinia, a 20-year-old vice president of the Harvard Republican Club, who said he would cast a ballot even though he opposed Trump.

“I will definitely vote, I just don’t know if I will be writing someone in or voting for (Libertarian) Gary Johnson or even voting for Hillary Clinton when it gets down to it,” said Khansarinia, who is registered to vote in heavily Democratic California. “Once this is over, come Nov. 9, we will need people here to rebuild the party.”