Trump struggles to gain traction with millennial voters in 2019

President TrumpDonald John TrumpThe Hill's Campaign Report: Democratic field begins to shrink ahead of critical stretch To ward off recession, Trump should keep his mouth and smartphone shut Trump: 'Who is our bigger enemy,' Fed chief or Chinese leader? MORE has struggled to gain traction among millennial voters in 2019, according to recent Hill-HarrisX polling data.

Trump's job approval rating among registered voters between the ages of 18 and 34 started off the year at 37 percent and has not broken through the 40 percent mark, dipping at one point as low as 30 percent.

The latest Hill-HarrisX survey showed the president with support from 39 percent of millennial respondents, down from 55 percent in mid-September.

The president's struggles with younger voters took hold after the partial government shutdown began in late December amid a standoff with congressional Democrats over funding for his proposed wall.

Since the Hill-HarrisX surveys began in late July, Trump's ratings among voters 35 and older have been more stable.

The president's approval rating among respondents between the ages of 35 and 65 has hovered around 47 percent during that period. His support has declined somewhat among voters older than 65.

A Hill-HarrisX poll released Wednesday found that 45 percent of all registered voters approved of the president's job performance.

Pollster Lee Miringoff on Wednesday tied the decline of Trump's approval rating among millennials to Democratic support of issues like gun control that have been championed by younger voters and the March for Our Lives movement.

"This is all a question of mobilization," Miringoff, the director at the Marist Poll, told Hill.TV's Jamal Simmons on "What America's Thinking."

"If there's the base on the president's side, he's also mobilizing a base on the Democratic base indirectly, or unintentionally," Miringoff added. "We saw it in the midterm turnout where young folks were much higher, and the biggest growth group of any age group."

The Hill-HarrisX poll has been conducted every two weeks since the end of July among a representative panel of 1,000 registered voters. The overall samples have sampling margins of error of 3.1 percentage points.

— Matthew Sheffield and Julia Manchester