Update: May 26, 4 p.m.:
Hispanic Leadership Fund President Mario Lopez said Ted Cruz has never held any leadership position with his group. Also, the group does not support amnesty, he said.
"If David Dewhurst wants to deceitfully lump us in with leftist organizations that actually do promote amnesty, then all he is accomplishing is demonstrating to Texas voters how intellectually shallow he is," Perez said.
Cruz spokesman John Drogin also confirmed that Cruz has never held any leadership position with that group.
Dewhurst spokesman Matt Hirsch said the campaign stood by the ad's contention that Cruz "helps run" two national organizations that support amnesty and that one of those organizations is the Hispanic Leadership Fund. He declined to provide proof that Cruz ever held a leadership position in the organization though noted that Cruz lists the organization on his LinkedIn page.
A new radio ad from Lt. Gov. David Dewhurst brought race and illegal immigration to the forefront of the U.S. Senate race Friday, the last day of early voting before Tuesday's primary.
In the ad, called "Amnesty," Dewhurst's campaign implies that former Texas Solicitor General Ted Cruz supports granting amnesty to illegal immigrants due to Cruz having served as a board member for two Hispanic groups, the Hispanic Leadership Fund and the Hispanic Alliance for Prosperity Institute.
The Cruz campaign and his supporters immediately denounced the ad Friday and were quick to point out that Cruz, who is Cuban, has long been a critic of amnesty proposals.
"That is the act of a desperate man clinging to power," Cruz said during a news conference in Fort Worth, according to The Dallas Morning News. "His lies are getting more and more ridiculous."
George P. Bush, son of former Florida Gov. Jeb Bush and nephew of former President George W. Bush, has leadership positions with both of the Hispanic groups at issue in Dewhurst's ad. He also is a founder of Hispanic Republicans of Texas, a group that has endorsed Cruz.
"When I first heard this false attack ad, I was offended not only as a Hispanic but as a Republican," Bush said in a statement. "We are a party of inclusion that welcomes the fastest growing demographic in our state that largely shares our conservative values of limited government, strengthening the family and supporting small business."
The Cruz campaign also released a web ad called "Desperate Dewhurst's Amnesty Lies" that criticizes the radio ad and Dewhurst's record on immigration.
Dewhurst senior adviser Jim Bognet accused Cruz of "playing the victim card."
"Ted Cruz is desperate and flailing, so he's taken a page out of the Democrat playbook," Bognet said. "Cruz's attacks today are absolutely and totally out of line. This is about Cruz’s deception and lack of character. Cruz is the one who chose to be involved and stand by these pro-amnesty groups."
Former Dallas Mayor Tom Leppert's campaign said the back and forth should help voters realize that neither Cruz nor Dewhurst is worthy of their support.
"It's unfortunate that Dewhurst and Cruz have engaged in constant mudslinging, tearing others down to try to build themselves up," Leppert spokesman Daniel Keylin said. "How can either end politics as usual when both are already perfect examples of what's wrong with Washington? Tom will continue to run a positive campaign and focus on sharing his detailed solutions to get our economy back on track and rein in the federal government."