A new study from the Pew Research Center shows a growing partisan gap in opinions on major issues, driven in part by Democrats' leftward drift.

Pew found Democrats have moved substantially left on a variety of issues while Republicans' views remain relatively constant. That was true across social and economic issues; Pew claimed that the split between Republicans and Democrats is more pronounced than any divides by race, gender, or socioeconomic status.

"This poll and some other recent ones show that Democrats are pulling more strongly to the left and Republicans are not pulling quite as strongly to the right as a general matter," said Karlyn Bowman, a senior fellow at the American Enterprise Institute who specializes in American public opinion.

One such leftward shift came in Pew's question about welfare. As to whether or not the government "should do more to help the needy, even if it means going deeper into debt," 71 percent of Democrats respond affirmatively, up 17 points over the past six years.

Republicans' opinions have barely shifted, down slightly from 25 to 24 percent. Additionally, some 76 percent of Democrats say "poor people have hard lives because government benefits don't go far enough"—the highest proportion of Democrats since Pew started asking the question in 1994.

Democrats have also substantially increased their support for attending to the interests of U.S. allies. Overall, the number of Americans saying as much has increased eight points since last year, a change which "has come entirely from Democrats," Pew says. Democrats and Democrat leaners have increased their concern about allies from 62 to 74 percent since President Donald Trump took office.

In the case of immigration, while Americans of both parties have grown more liberal, Democrats still lead the trend. When asked if immigrants are more a burden or a boon to the United States, 42 percent of Republicans say they strengthen the country, up from 30 percent in 1994. Over the same time period, the percentage of Democrats saying immigrants were a net benefit grew from 32 percent to 84 percent.

Other areas that have seen conspicuous change among Democrats and no concurrent change among Republicans include racial discrimination—64 percent of Democrats say black Americans cannot "get ahead" because of racial discrimination, up from 28 percent in 2010—and the belief that religion is required for morality—the number of Democrats saying "no" has risen 13 points since 2011, while the number of Republicans has remained roughly constant.

Pew's findings reflect a long-running and growing divide in American beliefs, Bowman said.

"On social issues, those changes have been happening for a very long time," Bowman said. "I think it's actually been moving for quite some time, and the Pew charts just document more recent, faster movement in the last couple of years, but it's certainly been happening for a long time."

Democrats' leftward shift helps to exacerbate an overwhelming partisan divide. Across ten questions Pew has asked of survey respondents since 1994, the difference between Democrats and Republicans averages 36 points. That is the highest rate ever, though the gap has been growing continuously since 1994, when the average difference was just 15 points. The gap between Republicans and Democrats "far exceeds divisions along basic demographic lines, such as age, education, gender and race."

"In nearly every domain, across most of the roughly two dozen values questions tracked, views of Republicans and Republican-leaning independents and those of Democrats and Democratic leaners are now further apart than in the past," Pew noted.

Particularly pronounced is the partisan split over President Trump. Eight percent of Democrats approve of Trump's performance in his first year, compared to 88 percent of Republicans who approve. That makes Trump's first-year approval ratings, "the most polarized of any president dating back to Dwight D. Eisenhower in 1953."

Distaste for Donald Trump and the leftward shift may go hand-in-hand, as Democratic leaders move the party's overall politics left in reaction against the president.

"The party is being pulled in a more liberal direction, there's no question about that," Bowman said. "I mean Elizabeth Warren's comment a few weeks ago essentially that this isn't Bill Clinton's party, we're not the party of welfare and crime. I think she's reflecting the views of many of the people in her party. And I think a lot of it happened during the Obama years."