5 things to watch for in the Texas primary

— -- Texas holds the first primary contests of the 2018 election on Tuesday and both parties are watching for indications of how the battle to control Congress may play out in November.

Democrats are hoping strong early voting by their party faithful is a prediction of a blue wave of enthusiasm that will give them back control of at least one chamber of Congress. Republicans hope Texas stays true to its red roots and quells any rising tide.

In the Lone Star state, both parties are running casts of colorful characters. The Senate race features outspoken, conservative incumbent Republican Ted Cruz.

Rising Democratic star Rep. Beto O’Rourke, who once played bass in the punk-rock band Foss, strongly outpaced Cruz in fundraising this quarter.

But the most colorful of them all has one of the most familiar last names in politics: Texas Land Commissioner George P. Bush. And he’s tying his campaign to one of his family’s biggest rivals: President Donald Trump.

This year also is the first time in 25 years that Democrats are running someone in every open possible race. Tuesday night could be the beginning of a watershed year for women running for (and potentially winning) public office.

Here are five key things to watch as polls close at 8 pm ET on Tuesday night.

Dems looking to capitalize on a changing Texas

Texas is one of four majority-minority states in America, with 40 percent of the state identifying as Hispanic or Latino. Democrats have been slowly attempting to flip GOP-controlled areas of the state for years, and this cycle is no different.

Turnout on the Democratic side will be a crucial barometer of enthusiasm in the party leading up to November.

Early voter turnout has been high among Democrats, according to state election figures in the largest fifteen counties. Throughout the 11 days of early voting, Democrats cast 465,245 ballots – nearly 45,000 more than Republicans - who cast 420,329 ballots in those selected counties.

Democrats have doubled their turnout in the 2014 midterm election in those counties. In Harris County, which includes Houston, Democratic turnout jumped from 30,108 in 2014 to 87,916 in 2018.

While the early voting numbers are revealing, political strategists caution voter turnout on election day still will be key to the outcome.

These numbers will offer the first snapshot of where the party stands in their never-ending quest to turn the state blue. While the suburban areas around Houston, Dallas, San Antonio and Austin are the immediate battlegrounds in the state, Democrats are also starting a push into redder areas of Texas, eyeing a number of open seats that have been GOP strongholds for decades.

A wave of retirements 

Eight of Texas’ 36 Members of Congress (22 percent of the delegation) are retiring this cycle, and six are those retirees are Republicans.

The contests to replace retiring Republican lawmakers, in particular, have drawn big GOP fields with more than 10 candidates running in some of these races.

Some of these GOP retirements are fallout from the #metoo movement.

GOP Rep. Blake Farenthold is retiring after questions arose around his use of taxpayer money to settle a lawsuit from a former congressional staffer, money which to date he has yet to pay back.

Rep. Joe Barton admitted to inappropriate texts with a woman.

While many of the GOP-held seats are not expected to be competitive, Democrats are hoping to pick up at least one open seat to help them make a dent in the 24 they need to retake control of the House.

Texas’ 21st Congressional District, where GOP Rep. Lamar Smith is retiring, may be the one to watch for a flip to blue.  

Cruz in trouble?

While neither primary in the Senate race is expected to be competitive, Democrats are hyping up O’Rourke as the man that may be able to take out conservative stalwart Cruz in November.

The 45-year-old O’Rourke, who has represented an El Paso congressional district since 2012, outpaced Cruz in fundraising by more than $1.5 million since the beginning of the year, according to FEC data. Since January, O'Rourke has raised nearly $2.6 million to Cruz’s $895,276.

O'Rourke has raised a total of $8.7 million so far this election cycle and had $4.9 million cash on hand as of Feb. 14. Cruz has raised a total of $7.2 million this cycle and had $6 million cash on hand.

Texas has not sent a Democrat to the United States Senate since 1988, so O’Rourke faces a tough battle, but Democrats are banking on a national wave that could carry him over the top. And while one flipped seat won’t hand them control of the Senate it could help them off-set any possible losses from the 24 seats they are defending in November.

Keep an eye on O’Rourke’s expected primary victory speech to see how he’ll try and frame a general election fight with Cruz.

Clinton-carried House districts

Democrats are hoping to flip three congressional districts Hillary Clinton carried in the 2016 election.

In Texas’ 7th Congressional District, one of ABC News' "18 for 18" races, progressive energy is flowing deeply into the Houston suburbs, an area at the crossroads of immigration, changing demographics and hurricane reconstruction. Political experts are eyeing the district as a key bellwether of whether or not the emerging Democratic wave will sweep the party back into power in the House.

Nine-term GOP incumbent Rep. John Culberson has represented the district since 2001, but he could be facing his toughest reelection yet with an eager field of Democrats fiercely battling it out for the nomination in a fight that recently devolved into intra-party bickering.

The Democratic Congressional Campaign Committee — which tends to reserve its attacks for Republican candidates — released negative research about one of their own primary candidates, Laura Moser, two weeks ago. LINK

The campaign committee cited a Washingtonian article in which Moser reportedly stated she would rather have her teeth pulled out without anesthesia than live in Texas, which the candidate says was taken out of context.

“It’s something we would expect from the other side but not our own party,” she said.

In response, DCCC communications director Meredith Kelly, in a statement to ABC News, said Moser's "disgust for life in Texas" disqualifies her from running.

Observers will be watching if the media attention around the controversy results in votes for Moser.

Meanwhile, the 23rd Congressional District — which stretches from San Antonio to the Mexico border with immigration taking center stage as a big issue for voters — is in play.

Rep. Will Hurd, who won reelection in 2016 by only 1.3 points, has earned a reputation for bipartisanship and working across the aisle, including with Rep. Pete Aguilar, a Democrat, on "Dreamer" legislation. Five Democrats are looking to unseat Hurd.

In the 32nd Congressional District, a crowded field of Democrats are running against Rep. Pete Sessions in a region which covers the wealthy suburbs of Dallas. Although Sessions is an influential Republican in the House, the district voted for Clinton in 2016, triggering a wave of Democratic challengers.

Former Housing and Urban Development Secretary Julian Castro is optimistic these three seats can go blue in the fall.

“Each of them has a number of Democratic candidates that are good candidates in the primary and will likely send a strong Democrat up against those incumbent Republicans in November,” he told ABC News’ Rick Klein on the "Powerhouse Politics" podcast.

A pink wave rising

Tuesday night marks the beginning of what could be a watershed year for women running for public office.

Of the state's 36 congressional representatives, only three are women. And more than 50 women running for Congress in Texas alone.

In many Democratic primary races, there are three or even four women running — women have been some of the top fundraisers too.

Two women are the top contenders for the Democratic nod to run against Culberson,

Lizzie Pannill Fletcher and Laura Moser saw their race get national attention after the Democratic Congressional Campaign Committee stepped in.

Moser is playing up her outsider credentials.

"I'm one of those women who never ever had it on my radar to run for office but was really mobilized by the election of Donald Trump,” she told ABC News.

Fletcher, meanwhile, has been endorsed by EMILY’s List and the Houston Chronicle.

And a Bush battle as a bonus

At one point in the past few weeks, George P. Bush pinned this tweet to the top of his official twitter page: “Proudly endorsed by President Donald J. Trump.”

In a tweet last week Trump praised Bush, the son of former GOP presidential rival Jeb Bush, and said he “backed me when it wasn’t the politically correct thing to do, and I back him now.”

Trump once labeled Bush's father “low energy Jeb”.

It’s also a clear sign that Bush knows he could be in real trouble if he heads to a runoff election in May. Three other Republicans, including a former land commissioner, are attempting to unseat him.

Bush’s race is one of several GOP primaries that could go to a May 22 runoff if no candidate garners a majority vote.

ABC News’ MaryAlice Parks, Mary Bruce and Soorin Kim contributed to this report.