Staggeringly high Democratic turnout in the Texas suburbs last week has the party bullish about capturing a half-dozen seats that slipped through its grasp in the 2018 midterms.

Democratic primaries in six GOP-held districts saw a roughly 100 percent increase in voters compared to 2016, according to a POLITICO analysis of turnout data. The spike indicates that a lethal recipe might be brewing for Republicans in the run-up to November: President Donald Trump's unpopularity in the suburbs, combined with rapid demographic change and an amped-up Democratic base.