When the Senate confirmed Rep. Tom Price (R-Ga.) in February as President Trump's health and human services secretary, few in Washington thought that, come June, the president would need to urge people to vote Republican in the special election to replace Price.

But it's Election Day in Georgia, and look at this:

Even though he spelled the Republican's last name wrong in that third (now deleted) tweet, the fact he's tweeting at all about this race underscores that what was supposed to be a quiet, humid special election in an upper middle-class Atlanta suburb to replace Price has turned into a battle. And both sides say it's a 50/50 contest.

That alone is remarkable. The Republicans have held Georgia's 6th Congressional District since the 1970s and, really, since the political realignment of the South.

But Republicans are at risk of losing it in the era of Trump to a 30-year-old Democrat with no legislative experience, Jon Ossoff. Ossoff has a slight lead in the polls, but operatives on the ground in Georgia on both sides say this race could come down to a few votes between him and the GOP candidate, former Georgia secretary of state Karen Handel. A recount is possible.

The logical question is: Why? Why is this race suddenly so competitive?

The admittedly unsatisfying answer is: It's hard to tell.

Special elections can be particularly useful tea leaves for studying the national mood, said Stuart Rothenberg, a nonpartisan elections analyst and columnist at The Washington Post. Most voters aren't paying much attention to the candidates when they go to vote, which means they're probably thinking big picture.

“When they think about choices, they tend to think big choices: change versus status quo,” Rothenberg said. “Keep the president, or send a message of dissatisfaction to the president.”

Or this special election could be just that: special, without any meaning beyond Georgia. Here are a few not-mutually-exclusive theories from Democrat and Republican operatives, both about the dynamics of this particular race and the national mood. Any one of these theories could either all be right or all wrong or somewhere in between:

1. Establishment Republican voters are sick of Trump: This is a Republican district (Price won it by 24 points in November), but it's not a Trump district (Trump won it by around a percentage point). Now it's possible those same Republicans who voted for Trump over Hillary Clinton decide they want to send a message to Trump and send a Democratic candidate to check him, Rothenberg said.

Overlay that onto the fact that Democrats in special elections in GOP districts in Kansas and Montana did better than expected this spring, and you could have a trend.

2. Moderate and liberal Democrats woke up: There are more Republicans than Democrats in this district, but it's possible that Democrats are so motivated by what they see happening in Washington they are campaigning and voting and engaging in politics as if they live in a swing district. This would be the dream scenario for Democrats, who hope that the fact this race is competitive portends that many, many more seats in the 2018 midterm elections will also be competitive. There are more than 70 seats that are more competitive than this race, according to rankings by the nonpartisan Cook Political Report.

“We can win everywhere,” said Alejandro Chavez, senior electoral campaign manager for the progressive group Democracy for America. “We just have to compete everywhere.”

3. There's been so much national attention that its competitiveness was inevitable: You can make almost any race competitive when it sets records as the most expensive House race in the nation. Ossoff raised a mind-boggling $20 million in the past three months.

And outside groups on both sides have spent millions. Thousands are knocking on doors and making phone calls for the candidates. You'd have to work harder in Georgia NOT to pay attention to this race than to pay attention.

Republicans are heartened by that. Come November 2018, Democrats (and their donors) will have to divide all this effort up by 20 or 30 districts next year. (Democrats have a list of 70 seats they hope to make competitive, and they need to net 24 seats to take back the House of Representatives.)

4. The candidates weren't great: I guarantee you this: Whoever loses will get cast by operatives in their party as a so-so candidate who lost the race for them. (Politics is a contact sport, people.) Handel in particular is vulnerable to this criticism. She failed to beat Ossoff outright in the first round of voting in April, and she failed to clear the field of the other 16+ GOP candidates who were running in April.

For now, all we know is that the special election to replace Price is surprisingly competitive.

We won't be able to truly answer why until this race is long over and we've tested these above hypotheses in the 2018 midterm elections.