(CNN) The focus on whether President Donald Trump's political base is splintering may be missing an even more important crack in his foundation.

Even as Trump faces a geyser of discontent from conservative leaders over his recent legislative overtures toward Democrats, previously unpublished results from an array of recent public polls find doubts about his performance and priorities resurfacing among the better-educated and especially younger Republicans who initially resisted him most during last year's GOP primaries.

Trump retains his strongest support from Republicans who are older or who lack a four-year college degree. But across several measures he's now facing discontent among the opposite groups: Republicans who are younger than 50 or who have obtained at least a four-year college degree. New polling through this week provides some evidence that Trump's recent legislative outreach to Democrats may be helping him recover somewhat with the latter, though not yet much with the former.

Still, the underlying contrasts underscore how firmly Trump's movement is rooted in older and blue-collar white America -- in the context of the Republican coalition and country overall.

"The problem for the party is they have handcuffed themselves to an anchor that is on the wrong side of history," says GOP consultant John Weaver, a frequent Trump critic and the top strategist for Ohio Gov. John Kasich.

Younger and college-educated Republicans both displayed less enthusiasm about Trump during the Republican primaries: while cumulative analyses of the 2016 GOP exit polls found that Trump won nearly half of voters without a college degree and over two-fifths of those aged 45 and older, he carried only about one-third of college-educated primary voters and just slightly more than that among those younger than 45.

But both of those groups largely rallied around Trump when he took office. Detailed results provided by Gallup from its daily tracking poll show that during Trump's first month in office -- from January 20 through February 18 -- the new President drew positive job approval ratings from just over four-fifths of both Republicans with and without a four-year college degree.

At that point, the gap by age was only slightly greater. Over his first month, Trump drew positive marks for his job performance from 88% of Republicans 50 and older, and 79% of those who were younger.

But Gallup results from August found the gap in attitudes toward Trump's performance widened on both fronts. In Gallup polling from the day after Trump's initial response to the violence in Charlottesville on August 12 through August 31, his approval rating among college-educated Republicans slipped to just 71%. That was down 12 percentage points from his standing with those well-educated Republicans in his first month of his term. Among Republicans without a degree, Trump retreated too, but only by seven percentage points, to 77% approval.

The age gap among Republicans opened even wider. Post-Charlottesville, Trump retained an 82% approval rating among Republicans older than 50, compared to just 67% among those younger than 50. His disapproval rating in late August among younger Republicans (at 28%) nearly doubled the level among older Republicans (15%).

As Trump has shifted gears in September toward negotiating with Democrats on the budget and young people brought illegally to the US as children by their parents, more recent Gallup results show narrowing in the education-, but not the age-, gap among Republicans.

In Gallup nightly results from September 1 through 17, Trump's approval among college-educated Republicans recovered to 77%, essentially matching his 78% showing among those without degrees. But the President's September approval among younger Republicans -- at 69% -- still lags far behind his 84% number with those older than 50, Gallup found. His disapproval rating among younger Republicans remains roughly double its level among older ones.

An array of other polls tracking personal assessments of Trump reflects a similar pattern, with big differences among Republicans by age and more modest, but still measurable, contrasts along educational lines.

When the non-partisan Pew Research Center polled Americans in late August on an assortment of Trump's personal characteristics, the President consistently faced resistance from about one-third of Republicans younger than 50. For instance, just 35% of younger Republicans and GOP-leaning independents called Trump even-tempered (compared to a 54% percent majority of older Republicans). Fully 35% of the younger group also described Trump as not honest (compared to just 20% among the older). A virtually identical 34% of younger Republicans called Trump prejudiced (compared to 28% of the older.)

On Pew's broadest question, just 26% of the younger Republicans said they liked the way Trump conducted himself as President; nearly as many (22%) said they disliked his conduct, and the biggest group (51%) said they had mixed feelings. Older Republicans were much more positive.

Across these same measures, college-educated Republicans were more likely than their non-college counterparts to ascribe negative terms to Trump, though the gaps weren't as large as the party's age divide.

The August CNN Poll conducted by SRSS closely tracked these patterns. According to figures provided by CNN Polling Director Jennifer Agiesta, that survey consistently found a slightly larger share of college-educated than non-college Republicans expressing negative views on questions such as whether Trump's first six months were a success, people were proud to have him as President, and whether his performance had increased or diminished respondents' confidence in his ability to do the job.

As with Pew, the gaps were greater by age, with just over one-third of Republicans younger than 50 saying they were not proud to have him as President and just under one-third indicating that his first six months had diminished their confidence in his capacity to serve.

Some recent state polls have unearthed similar patterns. The Marist/NBC surveys in Pennsylvania and Wisconsin found that compared with their non-college and older counterparts, considerably fewer Republicans who are college-educated or younger than 50 said they approved of Trump's performance or were proud of his conduct as President. In Pennsylvania, only about one-third of both college-educated and younger Republicans said they were proud of his conduct.

These same fissures run through some of the administration's principal issue thrusts. The Chicago Council on Global Affairs recently released polling results measuring Americans attitudes on trade. The survey found college-educated Republicans were considerably more likely than those without degrees to express positive views on trade deals such as the North American Free Trade Agreement.

The age contrast was even more dramatic, with younger Republicans much more positive about NAFTA and more likely to say the US benefits from international trade deals.

Likewise, surveys from Pew and other pollsters have found that younger and college-educated Republicans are considerably less likely than older and non-college members of the coalition to believe that undocumented immigrants should be denied any legal status, that legal immigration should be reduced, or that immigrants are more a burden than benefit to the country.

With these pockets of discontent persisting, some have speculated that John Kasich may challenge Trump in the 2020 Republican primaries. But Weaver, his adviser, says it's too early to conclude these divisions would provide a sufficient foundation for a plausible primary challenge to Trump.

"I don't know the answer to whether Trump can be beat in a primary yet," he said. "Ultimately the party is at a fork in the road -- do we go down a Trump-ian path that is going to be on the wrong side of history on so many issues and is not viable nationally...or do we throw off the yoke of Trumpism and build toward the future? I don't know if we get there in 2018 or 2020 or 2022, but whenever we do it's not going to be a pretty process."