NEW YORK (Reuters) - Carol Donovan became convinced 2018 could be a good year for Democrats in Dallas County, Texas, when so many enthusiasts jammed into the party’s annual fish fry fundraiser last October that they ran out of catfish.

What the county Democratic chair Donovan saw at the event is backed up by a new Reuters/Ipsos opinion poll, which found enthusiasm among Democrats is soaring ahead of elections on Nov. 6 that will determine whether Republicans maintain control over the U.S. Congress.

Across almost all demographic groups, more Democrats say they are certain to vote compared to poll results in 2014, the last non-presidential election year.

The Reuters/Ipsos poll has been tracking Americans’ interest in voting since 2010 and the polling on voter enthusiasm is built on data spanning 2014 to 2018, including data not readily available elsewhere.

White women Democrats over the age of 60 are leading the way: 74 percent said they are certain to vote on Nov. 6, up 18 percentage points from four years ago.

Among Republicans, 64 percent of older white women expressed certainty to vote, down 4 points from 2014 and a shift in the enthusiasm gap of 22 percentage points.

It is not just older women expressing an eagerness to vote.

The opinion poll, conducted from Aug. 20 to Sept. 16, found that Democrats have the edge in enthusiasm within most major demographic groups: college graduates, people between 18 and 34 years old - the so-called millennial generation - and mid-career adults.

Even among groups often thought to favor U.S. President Donald Trump, a Republican, like whites without a college degree and avid church goers, those who identify as Democrats are more interested in voting this year, while Republicans are not.

Carol Donovan, the Democratic Party chair in Dallas County, Texas, in an undated photo. Courtesy Jeff Dalton/via REUTERS

Enthusiasm is everything in the congressional elections, when turnout is typically lower than when the White House is also up for grabs. Only about four in 10 voting-age Americans bother to cast ballots compared to about six in 10 when it is.

When voters in one party are especially determined to be heard in a congressional election, it can swing control of the U.S. House of Representatives and the Senate.

In 2010, for example, months after Democrats passed President Barack Obama’s healthcare legislation, a surge in turnout among Republican voters helped their party retake the House, according to data from the Cooperative Congressional Election Study, a survey run by a consortium of academic institutions.

It is not unusual for the party out of power to have a greater interest in voting, said Jan Leighley, a political scientist at American University. But Trump cranks the interest level even higher among Democrats this year, she said, because he’s “undoing everything that Obama did – just trashing Obama’s record. That’s going to raise the stakes for Democrats.”

Trump also nominated conservative judge and former Republican Bush administration lawyer Brett Kavanaugh for the U.S. Supreme Court, another factor galvanizing Democrats to vote in November.

ENTHUSIASM OR JUST NOISE?

Donovan, the Dallas County Democratic party boss in a region of 2.5 million people, agreed Trump is the motivator.

“Some people are inspired to vote because they are afraid of what he’s going to do. And some are inspired because they’re so aghast at what he’s already done,” Donovan said.

Her office needed to print 50,000 more voter information packets because so many people were volunteering to get out the vote as the usual 75,000 ran out. Dallas County Democrats will run a candidate in every major race in November for the first time in at least 20 years, she said.

The Democrats' nominee for the U.S. Senate, Representative Beto O'Rourke, threatens to unseat incumbent Republican Senator Ted Cruz, according to a Reuters opinion poll.

Donovan’s Republican counterpart, Missy Shorey, said much of the excitement among Democrats has been drummed up by “extremists who are making a tremendous amount of noise.”

She has seen promising signs of enthusiasm among Republicans too. This year, about 250 people have established themselves as precinct chairs, nearly double the number from 2014, to help get out the vote.

“Just because Democrats are loud and screaming doesn’t mean that people are listening,” Shorey said.

There are a few bright spots for Republicans. Interest in voting is up about 4 points this year among Republicans between 30 and 39 years old and up about 2 points among college-educated women.

The Reuters/Ipsos poll was conducted online in English throughout the United States. It asked people to rate on a scale of 1 to 10 their interest in voting in November’s election, 10 signifying they are certain to vote.

Altogether, the poll gathered responses in 2018 from 14,620 adults, including 6,003 Democrats and 5,436 Republicans. The results were compared against a poll that ran from Aug. 20 to Sept. 16, 2014 with responses from 9,179 adults, including 3,625 Democrats and 3,058 Republicans.

The polls have a credibility interval, a measure of precision, of 1 percentage point for the entire group and 5 points for smaller groups such as older women Democrats.