Running against an eight-term Democratic incumbent, Silvestre Reyes, in a heavily Democratic district in 2012, O’Rourke possessed the progressive credentials necessary to challenge Reyes from the left. And in some ways, he did. While serving on the El Paso City Council, he had already called for the legalization of marijuana and championed a proposal—highly controversial at the time—to provide health benefits to partners of gay city employees.

Yet in Texas’ open primary system, with Republicans as well as conservative Democrats deciding between the two candidates, O’Rourke’s advisers saw an opening for O’Rourke to run to Reyes’ right, as well. So O’Rourke criticized elements of the Affordable Care Act, then-President Barack Obama’s signature health care overhaul. His position on Social Security suggested an openness to proposals floated by a group of congressional Republicans. And in one internal campaign upheaval that became so intense it left one of his friends and political allies weeping, O’Rourke considered de-emphasizing his position—the subject of a book he co-wrote—on legalizing marijuana.

The strategy worked. By the end of the campaign, Reyes became the only Texas incumbent to lose a primary in 2012. And O’Rourke won his first race for national office, the biggest credential in his likely presidential campaign less than a decade later.