Wins for black candidates

A historic upset overturned Democratic politics in Florida as Andrew Gillum, the liberal 39-year-old mayor of Tallahassee, overcame several aggressive opponents to become the first black nominee for governor in the state's history. He campaigned on a bluntly liberal message, calling for a single-payer-style health care system at the state level, and he earned the endorsement of Bernie Sanders and crucial financial support from mega-donors on the left such as Tom Steyer and George Soros.

His victory caps a season of breakthroughs for black Democrats running for powerful governorships, including next door in Georgia, where Stacey Abrams could become the country's first black female governor, and in Maryland, where Democrats nominated Ben Jealous, a former president of the NAACP.

Gillum is likely to face a difficult fight in the general election against U.S. Rep. Ron DeSantis, the GOP nominee who is a vocal ally of President Donald Trump, and Republicans have already signaled that they intend to brand Gillum as outside the political mainstream of his traditionally moderate state.

And in what may be a painful irony for some Democrats, Gillum's win was also a stinging loss for Gwen Graham, a former member of Congress who had hoped to become Florida's first female governor. Though she was seen as the front-runner going into the primary, Graham finished second, ahead of three wealthy male opponents but about 3 percentage points behind Gillum.

A Sun Belt test for Trumpism

DeSantis was not the only Trump loyalist nominated for office Tuesday night. Joining him were Rick Scott, the Florida governor, who is running for Senate against the Democratic incumbent Bill Nelson, and U.S. Rep. Martha McSally, who won the GOP nomination for an open Senate seat in Arizona.

These Republican candidates — all closely aligned with Trump — will test the durability of Trump's political coalition in two highly diverse states that he carried against Hillary Clinton in 2016. DeSantis and McSally have linked themselves particularly closely to the president this year to win contested primary elections.

The Midwest is often seen as the heart of Trump's political base, but Florida and Arizona, with 40 Electoral College votes between them, were just as decisive in his slim national victory. The ability of Republicans to hold onto these states in 2018 may say as much about Trump's political future as the pitched races of the Rust Belt.

Gender beats ideology

Graham's defeat was a disappointment for Democrats hoping to break a gender barrier in Florida, but Tuesday's elections provided as pronounced a display of female candidates' strength as any primary night this year. Democrats nominated women for six competitive House races in Florida — all but one of the contested seats now held by Republicans — and for two targeted House seats and an open Senate seat in Arizona.

In some cases, Democratic women easily beat back male candidates running markedly to their left, suggesting again that primary voters are looking more to identity than ideology to shape their choices.

In Central Florida, U.S. Rep. Stephanie Murphy, a 39-year-old moderate "Blue Dog" Democrat, won her primary by more than 70 percentage points against a male activist backed by liberals who included Alexandria Ocasio-Cortez, a House nominee from New York.

In South Florida, Donna Shalala, the 77-year-old former federal health and human services secretary, won a close primary for an open House seat against a younger male state legislator who criticized her from the left.