Jackson's nomination went into free fall as reports emerged that alleged Jackson led a hostile work environment, over-prescribed drugs and possibly drank on the job.

Tom Steyer, one of the biggest Democratic donors in the country, openly mulled spending on O'Rourke's behalf via his environmental super PAC, NextGen America.

Cruz, a Texas Republican, is at the forefront of revamping the U.S. Senate's internal sexual harassment policies. Last year he joined a New York Democrat in introducing legislation proposing such an overhaul.

Democrats took a shellacking during President Barack Obama's first midterm election in 2010, and U.S. Rep. Solomon Ortiz's loss was one of the biggest surprises. Eight years later, some are wondering if Republicans have some overly confident incumbents unprepared for a potential "blue wave" in November.

A new Quinnipiac University poll of Texas voters finds 47 percent support Cruz, the Republican incumbent, while 44 percent back O'Rourke, an El Paso Democrat.

U.S. Sen. Ted Cruz's campaign will report raising $3.2 million in the first three months of this year, less than half the $6.7 million his Democratic rival has said he will report for the period.

The decision could spur Republicans in Texas to seek leadership positions. Fundraising in the state and elsewhere could also be affected. 

Both U.S. Senators from Texas questioned the embroiled Facebook CEO about the content on the social networking site. Cruz accused Zuckerberg of engaging in "bias and censorship."

"While I planned on serving out the remainder of my term in Congress, I know in my heart it's time for me to move along and look for new ways to serve," the Corpus Christi Republican, who has been dogged by sexual harassment allegations, said in a statement.

O'Rourke also said he doesn't want to repeal the Second Amendment, and that taxes are too low for corporations. 

In last month's Republican primary, former Texas Water Board Commission Chairman Bech Bruun came in first but by a narrower margin than many expected, drawing more attention to runner-up Michael Cloud ahead of next month's runoff.

Cornyn, the most powerful Texan in Congress, attached the measure to a $1.3 trillion omnibus spending bill.

The Democratic Congressional Campaign Committee telegraphed its preferences Thursday in two primary runoffs for U.S. House seats in Texas, one month after its effort to torpedo a Houston Democrat's congressional bid appeared to backfire.

The massive spending bill Congress passed Thursday includes $1.6 billion allocated for a border wall but fell far short of the Trump administration's demands, and Democrats were able to exact significant restrictions on the wall's construction.

Leaders in the U.S. Senate, including one of the two senators from Texas, have spent the past two days issuing a warning to President Donald Trump: Do not fire special counsel Robert Mueller.