A former spokesperson for Texas Sen. Ted Cruz's presidential campaign blasted Donald Trump in a series of tweets on Thursday for softening his tone on immigration reform, and said Trump's remarks show he belongs in the "Gang of 9," a reference to the "Gang of 8" immigration plan that conservatives rejected.

"The issue isn't amnesty (although we can call it the Gang of 9). The issue is even on his signature issue he's without principle," tweeted Ron Nehring. "This is exactly what Sen. Cruz warned about on May 3. That every Trump idea is subject to future reversal."

On May 3, the day of Indiana's Republican primary, Cruz launched a searing attack against Trump after he floated a tabloid report that suggested the Texas senator's father may have been linked to the assassination of former President John F. Kennedy.

"This is nuts. This man is a pathological liar," Cruz charged. "He doesn't know the difference between truth and lies. He lies practically every word that comes out of his mouth."

Cruz declined to endorse Trump during his now-infamous speech at the GOP convention. But Nehring said Republicans who have stuck by Trump will eventually end up being embarrassed by him.

Nehring said "plenty of people support amnesty," but the real issue behind Trump's immigration reversal is him "being on multiple sides of an issue nearly concurrently." He pointed to Trump's initial call to bar non-American Muslims from entering the U.S. as another policy on which he's evolved.

Because he lacks experience and has demonstrated his policy prescriptions are ever-changing, Nehring predicted that Hillary Clinton will "pull Trump apart like warm bread" in the first presidential debate.

"Trump keeps handing her ammo to use in 9/26 debate. 'Which Trump is America getting? Nobody knows,'" he wrote on Twitter.

Nevertheless, the former Cruz spokesman said there is still time for Trump to "turn this race around" so long as he stops "campaigning for President of Great Britain."