Washington (CNN) Republican Rep. Mark Sanford became the latest proof point that fealty to President Donald Trump -- much more than purity on the issues -- matters most in GOP politics.

The South Carolina congressman's loss in Tuesday's primary was the most stunning outcome on a day that voters in Virginia, Maine, Nevada and North Dakota also went to the polls.

In Democratic primaries -- particularly three key House races in Virginia -- the theme of this spring's primaries continued: Female candidates are winning at unprecedented rates and often by large margins.

Here are six things we learned in Tuesday's primaries:

Sanford pays for criticizing Trump

Arizona Sen. Jeff Flake was driven into retirement. Tennessee Sen. Bob Corker couldn't win the White House's support to run for re-election. Alabama Rep. Martha Roby was forced into a runoff.

And on Tuesday, Sanford became the latest Republican punished by voters for criticizing Trump, losing narrowly to state Rep. Katie Arrington.

Arrington's campaign was based on the premise that Sanford -- who has criticized Trump's style and questioned his knowledge -- is insufficiently supportive of the President. It's the same reason Alabama Rep. Martha Roby, who blasted Trump after the "Access Hollywood" tape became public in 2016, is headed to a runoff to defend her seat.

Trump weighed in himself less than three hours before the polls closed Tuesday. He tweeted: "Mark Sanford has been very unhelpful to me in my campaign to MAGA. He is MIA and nothing but trouble. He is better off in Argentina. I fully endorse Katie Arrington for Congress in SC, a state I love. She is tough on crime and will continue our fight to lower taxes. VOTE Katie!"

Sanford made enemies as governor in 2009, when he disappeared to Argentina during an extramarital affair. That scandal loomed large in the race, with both Trump and Arrington mocking the excuse Sanford had initially used in covering up his affair: that he'd been "hiking the Appalachian Trail."

In an ad, Arrington urged voters to tell Sanford to "take a hike."

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Nightmare scenario for Virginia Republicans

Corey Stewart, the bombastic conservative who built his public image on championing the Confederate flag and monuments like Charlottesville's Robert E. Lee statue and has appeared with white nationalists, won the Republican Senate nomination

State and national Republicans admitted there's virtually no chance Stewart will defeat Democratic Sen. Tim Kaine in the fall.

Their bigger worry, though, is how Stewart's presence on the ballot could lead Republican voters to stay at home, hurting the party in several competitive House races.

"I am extremely disappointed that a candidate like Corey Stewart could win the Republican nomination for US Senate," former Virginia Republican Lt. Gov. Bill Bolling tweeted. "This is clearly not the Republican Party I once knew, loved and proudly served. Every time I think things can't get worse they do, and there is no end in sight."

Brian J. Walsh, a Republican strategist who has worked on Senate campaigns, tweeted: "Can we just skip past the part where the media focuses on all the idiotic, racist & embarrassing things Corey Stewart will say & do the next five months and just acknowledge Tim Kaine won his re-election tonight. And he has Stewart voters to thank for it."

Democrats turn to women in key Virginia House races

Women will represent Democrats in all four of Virginia's competitive House races in November, the latest example of the party turning to women to unseat vulnerable Republicans in the Trump era.

On Tuesday, three women -- Elaine Luria, Abigail Spanberger and Jennifer Wexton -- won Democratic primaries. Earlier this year at the party convention, journalist Leslie Cockburn won the nomination in Virginia's 5th Congressional District.

"Women have been leading the resistance, leading in activism and come November they will lead the way in Democrats taking back the House," said Christina Reynolds, top strategist for EMILY's List, a Democratic organization that recruits and funds pro-choice Democratic women to run for office. "Virginia is a key part of that effort and EMILY's List is proud to stand with the women running in these targeted races."

A record number of Democratic women have filed to run for Congress since Trump stepped into the White House, with many telling CNN that they chose to run in response to Trump's presidency.

To date, 476 women have filed to run for the House in 2018, according to the Center for American Women and Politics at Rutgers University, surpassing the 272 who filed in 2016.

Democratic momentum continues in state legislative special elections

Democrats notched another win in state legislative special elections on Tuesday, the party's 43rd red-to-blue flip since Trump stepped into the White House last year.

Caleb Frostman, the Democrat running in Wisconsin State Senate District 1, claimed victory in Tuesday's special election and Frostman's campaign manager, Hannah Akbik, told CNN that Republican Andre Jacque conceded the race in a phone call with the Democrat. Jacque confirmed his concession in a phone call with CNN.

The district, which stretches up past Green Bay along Wisconsin's northern peninsula, has traditionally been Republican, with the GOP incumbent who ran in 2014 winning with 62% of the vote.

While it was not all good news for Democrats in Wisconsin on Tuesday -- Ann Groves Lloyd, the Democrat running in the special election in Wisconsin State Assembly District 42, conceded to her Republican opponent -- national Democratic operatives argue their showing in state legislative races shows voters are prepared to rebuke the President in November.

Marquee Senate races take shape

Two low-key primaries went exactly as expected Tuesday.

North Dakota Republicans chose Rep. Kevin Cramer to challenge vulnerable Democratic Sen. Heidi Heitkamp. And Nevada Democrats picked Rep. Jacky Rosen as their nominee against Republican Sen. Dean Heller.

The drama evaporated from both races after direct intervention from Trump and his political team to convince Cramer -- who'd already publicly said he wouldn't run -- to change his mind and launch a campaign in February. A month later, Trump and his 2020 campaign manager Brad Parscale pushed Danny Tarkanian out of the GOP primary against Heller, eliminating a serious threat to the nation's most vulnerable Republican incumbent.

The two primaries were sleepy Tuesday, but will be among the nation's most important battlegrounds in November.

Ranked choice makes for a long night

Election nights are long -- no matter what.

But asking voters multiple questions on each race further drags things out. So far, CNN has been unable to project a winner in the Maine House District or either the Democrat or Republican primary for Maine governor.

While you wait, though, check out this is saucy video of one of Sen. Angus King's opponents, who ran unopposed for the Republican nomination, has online.

He's a long shot.