Former President Donald Trump‘s interest in selecting Sen. Marco Rubio (R-FL) as his vice president is setting off alarm bells for Democrats.

The Florida senator and one-time rival of Trump has turned into a reliable ally and offers the former president a direct line to a bloc Republicans have been flirting with taking from Democrats for years — Latino and Hispanic voters. While Latino and Hispanic voters aren’t a monolith, creating in-roads with them would put several states Democrats have taken for granted in recent cycles in play, Michael LaRosa, who is a former press secretary for first lady Jill Biden and special assistant to President Joe Biden, wrote in an op-ed for the New York Times.