CNN election guru stunned as Trump's grip on the GOP revealed in Texas

CNN election guru John King was stunned on Tuesday after the Texas Senate primary race showed how much President Donald Trump's grip on the Republican Party had grown.

Scandal-plagued Republican Attorney General Ken Paxton defeated incumbent Sen. John Cornyn (R-TX) resoundingly in the runoff elections, with CNN and the Wall Street Journal calling the race for Paxton just after polls closed at 9 p.m. ET. Paxton will face Democratic Texas state lawmaker James Talarico in the November election.

King told CNN's Kaitlan Collins during a segment on "The Source" that Paxton's margin of victory showed just how strong Trump's grip over the Republican Party is, even though he remains underwater in national polls.

"President Trump is incredibly weak nationally right now; his national poll numbers are down. He's underwater," King said. "The Iran war is unpopular. Gas prices are up. However, the president has shown yet again in Texas his power over the Republican base."

King pointed to rural north Texas, where he said Trump would carry the small counties by between 80% and 90% of the vote. During the primary, Cornyn made a strong showing in that part of Texas. But just three months and one Trump endorsement later, it was like Cornyn had never been to that part of the state.

"The numbers are impressive for Mr. Paxton tonight," King said.