Democrat Rep. Beto O'Rourke, who is competing to take Texas Sen. Ted Cruz's seat in 2018, is fundraising off Cruz's refusal to un-endorse Roy Moore, the Alabama Republican Senate nominee who is facing allegations of sexual misconduct with teenage girls.

"Ted Cruz has endorsed Roy Moore, and since this news broke yesterday, Cruz has called the allegations 'troubling' – but he has not pulled his endorsement," O'Rourke said in a fundraising email Friday. "It's not that complicated, Ted Cruz: we're talking about potentially elevating a man who preyed on young girls to the U.S. Senate."

O'Rourke has expressed confidence he can beat Cruz, a Republican, in a 2018 general election in deep red Texas, and there has been some polling evidence to suggest at least a competitive contest.

The bombshell Washington Post report published Thursday contains accounts from four women alleging Moore sought sexual relations with them when they were teenagers. According to one of the allegations, Moore sexually assaulted a 14-year-old girl more than 30 years ago.

In response, Cruz put out a statement calling the allegations "serious and troubling allegations" while also urging caution before jumping to conclusions.

"These are serious and troubling allegations," Cruz said. "If they are true, Judge Moore should immediately withdraw. However, we need to know the truth, and Judge Moore has the right to respond to these accusations."

Moore forcefully denied this story while speaking to Sean Hannity on his radio show Friday. "These are allegations are completely false and misleading," Moore said. His response to the allegations from the other three girls were less clear.

After this interview two Republican senators, Mike Lee of Utah and Steve Daines of Montana, pulled their endorsement of Moore.

Senate Majority Leader Mitch McConnell, R-Ky., said Thursday that if the allegations are proven true, Moore "must step aside." Meanwhile, some other top Republicans, like Mitt Romney and Sen. John McCain, R-Ariz., have called on Moore to resign.

Cruz, along with Sen. Rand Paul, R-Ky., are among those remaining top Republican lawmakers to not retract their endorsements of Moore.