Democrats want to make Texas blue — or at the very least, purple — and a massive surge in voter enthusiasm is giving them hope.

After 11 days of early voting — which ended last Friday — Democrats are going into the primaries having shown extremely high levels of enthusiasm. Democrats doubled early voting turnout compared to the 2014 midterms and beat turnout numbers from the 2016 presidential election year by 4 percent.

Meanwhile, Republican early voter turnout declined 37 percent compared to 2016, with Democrats casting 45,000 more ballots than Republicans in the early voting period.

With a primary Election Day on Tuesday that will determine the Democratic and Republican frontrunners for all 36 congressional districts, a US Senate seat, and the governor’s office, Democrats are hoping this early surge of energy among their base can carry through to November. Most races will likely lead to a runoff election in May.

The energy is beginning to spook Republicans in the state. Republican Gov. Greg Abbott is up for reelection, and his campaign told supporters the energy “should shock every conservative to their core.”

At a GOP event, Texas Sen. Ted Cruz told supporters that Democrats would “crawl over broken glass in November to vote,” warning that Republicans “could get obliterated at the polls.”

“Here’s the thing we don’t know yet: if tomorrow is a big Republican turnout day or not,” Matt Mackowiak, a Texas-based conservative strategist said. “If it is not a big turnout day there is going to be some bed wetting.”

To be sure, early voting numbers don’t dictate the outcome of elections (Hillary Clinton’s early voting totals also looked pretty good going into Election Day), and November is still a long way away. But in a state notorious for having some of the lowest voter turnout in the country, this is a major sign that Democrats are motivated to get out to the polls.

What we can — and cannot — take away from the early voting numbers

Early voting numbers aren’t a good indicator of election outcomes, but they are a strong measure of voter enthusiasm; lots of early voters means lots of decided voters.

And in Texas’s biggest counties, Democrats surpassed their early voting numbers from the 2016 primaries, a presidential year. (Midterm election years usually see depressed voter turnout.) The state hasn’t tracked early voting in smaller, more rural counties, where Republicans likely have a much larger advantage.

Even so, the action is putting Republicans on their toes. Democrats have already won several deeply red state special elections around the country and come close in several others. Their high fundraising numbers also can’t be overlooked. Democratic favorite Rep. Beto O’Rourke, who’s aiming to challenge Cruz in November, has already out-fundraised the Republican incumbent.

More participation in primary elections doesn’t necessarily correlate with higher voter turnout in general elections. Republicans could — and have in the past — turned out in much higher numbers in the general election than in the primary. But there’s no question that enthusiasm is high among Democrats. This means that in November they’ll need to keep up their voter mobilization efforts in urban counties if they have any hope of winning over some Republican congressional seats.

As Vox’s Ella Nilsen explained, Democrats are eyeing three districts in Texas for November — around Dallas, Houston, and San Antonio — all of which Clinton carried by a couple of points in 2016 and have the potential to flip blue.

Democrats are banking on President Donald Trump’s unpopularity to push people to the polls. And Republicans are taking the threat seriously. Trump’s favorability in Texas isn’t as high as a state with a deeply red reputation would suggest. In February, 78 percent of Democrats found Trump to be very unfavorable and only 53 percent of Republicans found him to be “very favorable.”

Texas is known for having terrible voter turnout

Historically, Texas has consistently had some of the lowest voter turnout in the country.

The depressed electoral participation has been attributed to a host of reasons in the past, from acts of voter suppression to unmotivated voters. In 2010, slightly more than a third of eligible Texas voters decided the governor’s race. Less than 30 percent voted in the 2014 midterm cycle’s general election.

But as the Texas Tribune’s Alexa Ura and Ryan Murphy point out, Texas’s turnout is also deeply tied to demographics:

Hopes for a swell in voter turnout often hinge on the state’s burgeoning Hispanic population. But a breakdown of the population by age shows a third of Texas Hispanics aren’t even of voting age. In fact, those under 18 make up the state’s largest Hispanic age group. Meanwhile, those aged 45 to 64 make up the biggest age group of white Texans. To be clear, Hispanic adults participate in elections at lower rates than their white and black counterparts overall, which makes them an easy target for voter mobilization efforts. But when it comes to convincing Hispanic voters to play a bigger role in elections, it doesn’t help that they’re already starting from behind.

Generally speaking, Texas’s older population is much more likely to participate in elections than the young population, with the largest turnout from voters 65 and up. So while Texas is a young state, older Texans make up most of the vote.

Democrats are hoping Trump’s unique unpopularity — and his targeted attacks on the Hispanic population — can be enough to change the tide.

The enthusiasm for the primaries is proving to be some encouragement.