Texas has been a Republican bastion for a quarter century, leaving little incentive for national Democrats to invest in local candidates and help them get back in the game.

Instead, Democratic and Republican candidates have used Texas as an ATM on their way to winning offices in other states.

But now, Republicans nationwide and in Texas are in trouble. Democrats have performed well in solid GOP congressional districts in various special elections, including Tuesday’s contest in Ohio.

The trend could continue in Texas, where Democrats are eager to turn the tables after the election of President Donald Trump. They have their first chance to win a statewide contest since 1994 — the U.S. Senate race between Beto O’Rourke and incumbent Republican Ted Cruz. They even have a strong shot at picking up at least three congressional seats, including the one held by longtime Dallas Rep. Pete Sessions.

Because of these opportunities, Democrats should urge their donors to deposit the resources needed to flip the longtime Republican stronghold.

Texas is the biggest prize in politics. Once it becomes a true battleground, Republicans' ability to win the White House will be seriously diminished. It could spell the end of the Republican Party as we know it and shorten the controversial era of Trump. There's no GOP path to the White House without Texas.

U.S. representative Pete Sessions, of the 32nd district, spoke at a campaign kickoff event at The Highland Dallas hotel in Dallas in June. Sessions, a Republican and the incumbent, is running against Democrat Colin Allred. (Andy Jacobsohn / Staff Photographer)

Tight Senate race

For his part, Cruz has acknowledged that it’s going to be a tough race. He’s urged conservatives to take the threat from the El Paso Democrat seriously, telling supporters in Dallas that there are only two ways to run: "Scared or unopposed."

A recent Texas Lyceum poll has Cruz leading O'Rourke by 2 percentage points. Another from Quinnipiac University puts the spread at 6 points.

O’Rourke is raising more campaign cash than Cruz, and his large crowds indicate an enthusiasm Democrats haven’t seen in Texas since Barack Obama toured the state in 2008.

Cruz is still the favorite, and there are usually more Republican voters than Democrats. But the Trump effect has scrambled many of the norms. It's hard to forecast what turnout will look like.

O’Rourke needs to capture some Republicans to win, while Cruz is confident that if conservatives vote, he’ll be re-elected.

The Trump effect

With the exception of the Cruz-O'Rourke showdown, statewide wins like governor, lieutenant governor and attorney general are still a pipe dream, particularly for donors looking for a sound investment. Texas Republicans have their own brand, and it's tougher to nationalize a race in a state with such a strong identity.

The greater opportunities are down ballot.

In response to the stunning election of Trump, Democrats have responded with better organization and an enthusiasm that has resulted in noticeable results, if not outright victories, across the country.

In Tuesday's special election in Ohio's 12th Congressional District, Republican state Sen. Troy Balderson was leading Franklin County Recorder Danny O'Connor by less than 1 percentage point, too close to call the race. In 2016, Trump won that district by 11 percentage points.

Rep. Will Hurd (left), a San Antonio Republican, and Rep. Beto O'Rourke, D-El Paso, received an award for civility in public life on July 17 from Allegheny College. The ceremony took place at the National Press Club. (Todd J. Gillman / Staff)

That result mirrors what's been going on in most of the federal special elections across the country. In places that Trump won easily in 2016, or that have been red for a long time, Democrats have made significant gains. The theory is that if they can compete in areas that are overwhelmingly Republican, perhaps they can score wins in districts that are significantly more Democratic.

Hillary Clinton beat Trump in 25 congressional districts represented by Republicans, three in Texas. She won by 2 percentage points in Sessions' district, where Dallas lawyer Colin Allred has pulled ahead of Sessions in fundraising.

Clinton eked out a 1-point win in the Houston district where Democrat Lizzie Pannill Fletcher is challenging Rep. John Culberson, but her margin was larger — 4 points — in the swing district represented by San Antonio Republican Will Hurd, who's facing Army veteran Gina Ortiz Jones.

These three and five other congressional districts in Texas that Clinton won, or where Trump won by a small margin, offer Democrats a better chance of winning in November than they had in Ohio's 12th district.

Winning a few of these seats would help Democrats flip the 23 they need to take control of the House.

It’s clear that Texas — at long last — is moving closer to becoming a true battleground, which should excite anyone who longs for true competition and a legitimate exchange of ideas.