Voters are adding to the uncertainty by threatening to buck the parties they typically support. Republicans ill-disposed toward Mr. Trump are threatening to stay home or vote for Mrs. Clinton, while some Democrats who don’t like Mrs. Clinton or feel abandoned by their party are gravitating toward the presumptive GOP nominee.
The election is four months away, but early evidence suggests a larger-than-usual share of the electorate might switch sides this fall, with Republican women, in particular, more open to backing Mrs. Clinton, and white men who identify as Democrats rallying around Mr. Trump. The prospect of voters crossing party lines makes it more complicated for Mrs. Clinton, Mr. Trump and candidates down the ballot to turn out supporters on Election Day. ...
Mr. Trump’s opposition to free trade and illegal immigration has drawn white Democrats and independents who feel culturally isolated or economically distressed, while many higher-educated Republicans who don’t like Mr. Trump view Mrs. Clinton as the steadier commander in chief, polls show. ...
To gauge the propensity of voters to jump party lines, Deep Root pollsters measured support for Mr. Trump against professed support for an unnamed Republican congressional candidate—a so-called generic GOP candidate. Mr. Trump runs 27 percentage points behind the generic candidate among white, college-educated Republican women, and 20 points behind among Republican women who didn’t graduate from college, according to the Deep Root data.
But he runs more than 10 percentage points ahead of that generic Republican among white men who identify either as Democrats or independents. He also runs stronger among white Democratic women and the least-partisan Democrats.
Those findings are in line with Wall Street Journal/NBC polling data that show Mr. Trump runs far behind where 2012 Republican nominee
Mitt Romney was among white women with college degrees, but performs much better than Mr. Romney did among white men who didn’t attend college.
Democratic operatives say that trend is consistent with their own survey data, as well.