Congressional elections are zero-sum affairs. Candidates vie for a seat, the winner earns the opportunity to serve, and the loser gets nothing. No one gets a “nice job keeping it close” trophy.

That said, as we were reminded last night, context is everything.

Arizona’s 8th congressional district is a heavily Republican area. Donald Trump won here by 21 points in his presidential race, and GOP voters enjoy a 17-point registration advantage. In yesterday’s special election. Republicans ran an experienced state lawmaker, while Democrats ran a first-time candidate. Common sense suggested the race wouldn’t be close.

Except it was. As of this morning, Rep.-elect Debbie Lesko (R) defeated Hiral Tipirneni (D) by about five percentage points, 52.6% to 47.4%. Politico noted the growing anxiety among GOP officials.

Lesko’s single-digit margin is the latest evidence that Republicans face a punishing midterm environment, even in Trump-friendly territory. […] “Republicans shouldn’t be hitting the alarm, they should be slamming it,” said Mike Noble, a GOP pollster based in Arizona. He added: “This district isn’t supposed to be competitive, and so to see this margin, especially with the Republicans pouring in resources here – again, it’s a tough year.”

That point about resources is of particular interest: Republicans spent about $1 million to help push an established local candidate over the finish line, while national Democratic organizations largely ignored the contest. And Lesko still won a close race in a district Trump won by 21 points a year and a half ago.

Making matters quite a bit worse for Republicans, this wasn’t the first time. On the contrary, Democrats have already flipped two key “red” seats in Congress – Rep. Conor Lamb (D) won in a Pennsylvania district that Trump carried by 20 points, while Sen. Doug Jones (D) won a U.S. Senate special election in a state Trump carried by nearly 28 points – while Dem candidates kept it surprisingly close in U.S. House races in “red” districts in Montana, Georgia, Kansas, and South Carolina.

Donald Trump whined this morning that not enough people are paying attention to yesterday’s results in Arizona, but he doesn’t seem to understand what matters here: the outcome of this congressional special election offers fresh proof of his party’s troubles under his presidency.

And in case that weren’t quite enough, Republicans received even more discouraging news last night in New York, where Democrat Steve Stern flipped New York’s 10th Assembly district – a seat Republicans had held for more than three decades.

This is the 40th state legislative district Dems have flipped from “red” to “blue” since Trump took office.

If results like these aren’t making Republicans nervous, they’re not paying close enough attention.