Cruz said those figures should alarm Republicans nationally about Democratic turnout in 2020 — and make donors and party leaders recommit to investing in statewide and congressional races in Texas rather than assuming that Trump’s political brand and a few rallies will be enough.

The suburbs are where Texas Republicans are most vulnerable, Cruz said, noting that O’Rourke made inroads in 2018 in the highly populated suburbs outside Dallas and Austin, and in other urban areas.

U.S. census data show Texas is home to the nation’s fastest-growing cities, and an analysis last month by two University of Houston professors predicted that “metropolitan growth in Texas will certainly continue, along with its ever-growing share of the vote — 68 percent of the vote in 2016.”

“Historically, the cities have been bright blue and surrounded by bright red doughnuts of Republican suburban voters,” Cruz said. “What happened in 2018 is that those bright red doughnuts went purple — not blue, but purple. We’ve got to do a more effective job of carrying the message to the suburbs.”