Add the conservative Wilks family of Texas, among the biggest spenders in the presidential race so far, to the list of donors who won't support Donald Trump in the general election.

The fracking billionaires plan to sit out the presidential race after their candidate, Texas Senator Ted Cruz, dropped out of the race for the Republican nomination this week, according to Jon Francis, a Wilks family member and treasurer of the super-PAC that brothers Farris and Dan Wilks and their wives set up last year with $15 million of their own money.

Trump "could have just as easily (and probably more legitimately) run as a Democrat," Francis said in an e-mail. "He is certainly not a conservative. And, although one wouldn't have thought it possible, he appears to lie more than the current resident of the White House."

Francis didn't directly comment on the family's political plans, but a person with knowledge of their activities said they are likely to shift focus to other lower-level political races such as state contests in Texas. As of March 31, the Wilks' Keep the Promise III PAC had $8.3 million cash on hand, and had raised $2.2 million in addition to the $15 million from the family, elections records show.

The withdrawal of Cruz and John Kasich from the race this week left Trump as the de facto Republican nominee, likely to face Democrat Hillary Clinton in the general election. A billionaire real-estate developer turned entertainer, Trump disavowed fundraising during the primary contest, paying for most of his expenses out of his own pocket. But he's already laying plans to raise money from donors for the general election, where he may need to raise as much as $1 billion.

Many of the party's biggest donors oppose Trump. Paul Singer, a New York hedge-fund billionaire who is among the most active Republican fundraisers, recently helped arrange an anti-Trump advertising campaign. Charles Koch, the Wichita industrialist who oversees a powerful conservative donor network, has called Trump's suggestion of a travel ban on Muslims "reminiscent of Nazi Germany."

The Wilks brothers live in rural Cisco, Texas, and owe their fortune to Frac-Tech, a company that provides services to oil and gas producers. They are devout Christians who've spent millions opposing abortion and advocating for religious liberty.  They are said to be particularly disgusted by sexual comments that Trump made years ago during appearances on the Howard Stern Show, the person said.

"The fact is there are too many examples of despicable statements and actions to count in a reasonable amount of time," Francis said of Trump in the e-mail.

The Wilks' group focused virtually all of its spending on digital advertising supporting Cruz on sites like Facebook and YouTube.

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