Young men will likely be a key constituency for Republicans on the ballot this year, as the demographic has shifted dramatically to the right just since the last presidential election. This, as women of the same age cohort have moved further to the left. 

According to an aggregation of Wall Street Journal polls and the 2020 Associated Press VoteCast, men under the age of 30 have swung toward President Trump after supporting President Biden in 2020. Four years ago, a majority of men of all races voted for Mr. Biden. Now, though, 50 percent say they will vote for Trump, compared to 36 percent who planned on voting for Mr. Biden before he announced he was dropping out of the race earlier this month.

The latest Journal poll showing this shift to the right among young men was conducted after the June presidential debate, and was completed on July 3.  

Support for Democrats and Republicans alike has declined among women between the ages of 18 and 29, as well, though Democrats are the overwhelming favorite to win the group.

In total, Mr. Biden held a 30-point advantage over Trump in the July poll among young women. On the congressional ballot, Democrats hold an even larger margin, 34 percent, over their GOP counterparts.

Young men say they prefer a Republican-controlled House to stay in power, with a 12-point lead for Speaker Johnson and his colleagues among the group. 

On specific issues, women are much further to the left than men of their age. On taking action to combat climate change, a net of 67 percent of women say something should be done, compared to 32 percent of men. Support for legal abortion, too, has a 53-point net positive with young women, while among young men that spread is 16 percent in the positive. 

On more hot-button cultural issues, men are again much further to the right. A slight majority of women — just a 2-point net positive — say that children should be able to “pick their gender identity” without parental approval. Young men, on the other hand, are overwhelmingly opposed to that proposition, with a net negative 33 percent of men between the ages of 18 and 29 agreeing with the statement. 

Trump may also have a significant economic policy advantage with young men come November. A net of 23 percent say Trump’s signature 2017 tax cuts should be extended beyond their planned 2025 expiration, while a net negative of 20 percent among women say the taxes should remain. 

Young women agree with Vice President Harris’s assertion and central campaign theme that Trump and his running mate, Senator Vance, plan to take rights away from Americans. “What we’re worried about is our rights being taken away,” a Sharpsville, Pennsylvania, resident, Maggie Kelso, told the Journal. “If I had to guess why a lot of women are leaning very strongly toward more liberal issues, it’s that we’re afraid.”

“If Americans re-elect Trump, it would say that this country would rather be afraid of change, afraid of taking a step forward,” Ms. Kelso said. 

Before he dropped out of the race, Mr. Biden was trailing Trump among voters under the age of 40 — a group he won overwhelmingly in 2020 and that has helped power Democratic victories up and down the ticket for decades. 

According to a poll of voters under the age of 35 from Axios and Generation Lab, Mr. Biden had a lead of 6 points — far below the 24-point margin he had among those under the age of 30 and the 12-point margin he had among those between the ages of 30 and 39 against Trump four years ago. 

Ms. Harris leads Trump among those under 35, but not by the same margin Mr. Biden won in 2020. She has a 20-point lead — 60 percent to 40 percent — among the age group.