Even Martha McSally's viral video of her gracious concession could not take the sting out of the stunning nature of her defeat in Arizona. For the first time in 30 years, Democrats have won a Senate seat in the state. For Republicans, Kyrsten Sinema's narrow but undeniable victory over McSally has become one of the largest red flags to emerge from the midterms.

The concession caps a week of mixed-to-poor results in the elections. The brightest spot for Republicans was Florida, where the party did surprisingly well in a competitive state that they must win in any scenario to hold the White House in two years. The state has initiated recounts in its gubernatorial and Senate contests, but the gaps are so large that any reversal of the GOP candidates' leads would be unprecedented.

Otherwise, though, the results offer little cheer for Republicans. Losses in the House look somewhat larger than first assumed and may run as high as 40 seats when all the counting concludes. Republicans lost one of their own Senate incumbents, Dean Heller in Nevada, which polling had suggested might be closer than the eventual 5-point loss. The GOP did score three other Senate pickups, but only in deep-red states that President Trump won two years ago. Five other Trump states sent Democratic incumbents back to Washington, including "blue wall" states Wisconsin, Michigan, and Pennsylvania.

In Arizona, they lost the only open seat they had to defend. The circumstances of that loss still look puzzling. On the same ballot, incumbent Republican Gov. Doug Ducey cruised to victory over David Garcia by more than 300,000 votes, a 15-point victory. McSally scored 200,000 fewer votes than Ducey did despite a massive Republican lead among early voters. Trump didn't score an overwhelming win in Arizona two years ago, but he got 49 percent of the vote to Hillary Clinton's 45 percent. McSally didn't get past 48 percent in the three-way race — in a state with a Cook index rating of R+5.

The loss leaves Republicans on defense, both narrowly and broadly. Jon Kyl, appointed by Ducey to replace the late John McCain in the state's other Senate seat, has made it clear he will retire in the next few weeks. Ducey could appoint McSally to the seat, but she would have to run again in a special election in 2020 for the final two years of the term at the same time Trump will seek re-election. Since she lost a statewide election already, Ducey might have to consider appointing someone else in the spot instead. Either way, after winning the open Arizona seat this cycle, Democrats will likely pour more resources into the opportunity to hold both of the state's Senate seats in two years.

The failure to hold Jeff Flake's open seat creates other headaches as well. In the 2020 election, the vulnerabilities in Senate races will be reversed. Democrats will only defend 12 seats while Republicans will defend 22. The GOP won't face the same daunting task of defending 10 seats in hostile territory, as Democrats did, but they will have to spread their resources further.

Besides having to defend an appointee in Arizona after a stunning pickup by Sinema, they will also need to re-elect Cory Gardner in Colorado, which has also trended Democratic over the last few election cycles. Susan Collins will face a slightly Democratic electorate in Maine, which may not appreciate her full-throated support for Brett Kavanaugh. Joni Ernst will try for her first re-election in Iowa, where two Republican House incumbents lost to Democrats last week. Thom Tillis barely won his last re-election bid in North Carolina and can expect another stiff challenge. The only real bright spot for the GOP in 2020 will be in Alabama, where Doug Jones can expect his unlikely run as senator to end if Republicans nominate anyone besides Roy Moore.

Even worse for the GOP, the loss in Arizona highlights their tenuous hold on the key states necessary to winning the Electoral College. The losses in the "blue wall" states show that normal or higher Democratic turnout will block Trump from that path to victory, unless Clinton tries running again. Without those states, Republicans can only get to 260 votes using the 2016 election results as a template. Republicans would have to make a big push in Virginia, or perhaps some combination of Colorado, Nevada, and New Hampshire in order to get the 10 electors necessary to win without the Midwestern flips that made Trump president.

If Sinema's win means Arizona is in play — and Trump's 49 percent in 2016 already suggested it might be — then there is almost no place to make up the loss of those 11 electors. On top of that, the close election in Georgia's gubernatorial race also potentially puts that state in bubble status as well, with another 16 electors at risk in a state Trump won with only 51 percent of the vote. Suddenly, Trump has gone from 306 electors to just 249 or even 233.

Arizona turning purple should have Republicans wringing their hands for the next two years. Debate over the existence of a "blue wave" misses the point. Unless the GOP finds a way to attract large numbers of new voters to their banner, the 2020 cycle looks grim.

Editor's note: A previous version of this article misidentified the senators up for re-election in 2020. It has been corrected. We regret the error.