Two Texas Senate incumbents were in danger of being unseated Tuesday: Republican state Sen. Craig Estes was trailing challenger state Rep. Pat Fallon by about 40 points, according to early voting returns, while state Sen. Bob Hall was narrowly trailing state Rep. Cindy Burkett.

Meanwhile, Republican Angela Paxton was leading Phillip Huffines in the race for the open Texas Senate District 8 seat, which quickly became the most expensive primary for a state office this year.

The three Senate races were among a number of closely watched contests that highlighted divisions within the state's dominant party.

Those early results Tuesday hinted that GOP voters in some — but maybe not all — Senate districts are willing to support the same candidates as Republican Lt. Gov. Dan Patrick, who endorsed Hall and Paxton and provided some campaign help to one of Estes’ challengers.

Senate District 2

Burkett was holding on to a narrow lead, 51 percent to 49 percent, over Hall, according to early voting returns.

Burkett, a 59-year-old real estate agent, has been a member of the lower chamber since 2010 and currently chairs the House Redistricting Committee. Hall, a 75-year-old businessman backed by the Tea Party, won the seat in 2014 after beating incumbent Bob Deuell. Burkett was once an aide to Deuell.

If she maintains her lead, Burkett will face Democrat Kendall Scudder in November to compete for the district that covers part of eastern Dallas County and a large portion of East Texas, including Greenville and Sulphur Springs.

Senate District 8

According to early voting returns, Angela Paxton was winning just under 54 percent of the vote, leading Phillip Huffines, who had 46 percent, for the Republican nomination to a Texas Senate seat representing Dallas’ northern suburbs in what is the most expensive primary for state office on the ballot. It’s also been one of the nastiest races, pitting two well-known conservative families against each other.

Paxton, a 54-year-old former guidance counselor, is the wife of Attorney General Ken Paxton. Huffines, a 59-year-old real estate developer, is the twin brother of state Sen. Don Huffines. Neither candidate’s conservative credentials were in doubt, so the race divided some of the most powerful Republican players in Texas.

Angela Paxton is a beloved figure among Republicans in Collin County, where most of the district is based. Phillip Huffines was formerly the Dallas County GOP chairman and had to move into the district to run for the seat. The two are expected to have spent a combined $10 million, which would make theirs the most expensive Texas Senate primary in history.

On the campaign trail, Phillip Huffines touted his family’s business experience in booming Collin County. The Huffines family is well-known for its car dealerships and real estate developments. Angela Paxton, meanwhile, argued that constituents deserve a state senator with deeper roots in the county.

The winner will be a heavy favorite against likely Democratic nominee Mark Phariss. Republican state Sen. Van Taylor, who is vacating the seat to run for retiring U.S. Rep. Sam Johnson's place, was leading two GOP opponents for that seat Tuesday night.

Senate District 30

Meanwhile, Fallon was winning nearly 64 percent of the early vote and appeared likely to unseat Estes, who had 22 percent, for the Republican nomination to Senate District 30, which covers a wide swath of North Texas that includes parts of Tarrant, Denton and Collin counties.

Patrick spent $17,000 to conduct polling for Fallon in the race, a move that incumbent Estes said was “nothing more than a bribe to hire a yes man in the Texas Senate.” But on the campaign trail, Fallon said local officials repeatedly told him that Estes was largely absent.

Estes, a 17-year incumbent of the upper chamber, had won the GOP nomination by double digit margins over the past decade.

Fallon, a 50-year-old business owner, boasted endorsements from more than two dozen fellow state representatives. Estes, a 64-year-old business owner, last year announced that he had the support of a handful of state representatives from across his district, but at least two later decided to remain neutral after Fallon entered the race.

Carter, who oversaw the revitalization of an abandoned factory building in Nocona, was dramatically outraised by Fallon and Estes. Fallon is expected to easily beat Democratic nominee Kevin Lopez in November.

This article originally appeared in The Texas Tribune at The Texas Tribune is a nonprofit, nonpartisan media organization that informs Texans — and engages with them — about public policy, politics, government and statewide issues.