(Getty)

Republican Senator Ted Cruz could be under threat from a progressive rival.

The Senator for Texas’ reputation has struggled ever since his 2016 presidential bid, in which Donald Trump heavily targeted him as out-of-touch and weak.

Now Beto O’Rourke, a Democratic Congressman from the state’s 16th district, who has a strong record of backing LGBT rights, is on course to challenge him.

Rep. O’Rourke has already stunned onlookers with his fundraising abilities.

He has raised more money for a Senate run than any Democrat in the state before him.

O’Rourke has so far raised more than $13 million, including $6.7 million in the first three months of this year alone.

This achievement is all the more remarkable given he refuses to accept cash from political action committees.

All of the money raised to date has come from individuals keen to support a rival to the infamously anti-LGBT Cruz.

Elected as a member of the El Paso City Council in 2005, he pushed for domestic partnership benefits, despite recognising that they were “a very unpopular and politically inconvenient issue.”

Since being elected to Congress in 2012, O’Rourke has been a clear backer of LGBT issues.

He has an 85 percent score from the Human Rights Campaign for the last session of Congress.

He has staunchly opposed Kyle Duncan, one of President Trump’s nominees to the federal bench in Texas, speaking out against Duncan’s “long record of undermining LGBT rights.”

A Democrat has not won the state in 20 years, but as the tide turns on Cruz it could come into play for the first time.

Last year Cruz backed a GOP candidate who compared Christian ‘victims’ of equal marriage to Jewish people in the Holocaust.

Backing failed candidate Roy Moore, who had argued gay sex should be illegal, Senator Cruz said: “Judge Moore has a lifelong passion for the Constitution and the Bill of Rights, and he has the courage of his convictions.

“In the Senate, we need reinforcements; we desperately need strong conservatives who will stand up to the Washington status quo.”

He refers to “Judge Moore” even though Moore was ejected from the Alabama Supreme Court for abusing his authority in a bid to block gay weddings.