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FORT WAYNE, Ind. — Four days ago, the star-crossed, state-splitting alliance of Senator Ted Cruz of Texas and Gov. John Kasich of Ohio made its debut.

Three-and-a-half days ago, it began to show serious cracks.

And on Thursday, it seems, the arrangement reached its nadir.

Speaking to reporters before a rally with Carly Fiorina, his would-be running mate, Mr. Cruz was asked about the status of the agreement, which stipulated that Mr. Kasich would cede Indiana to Mr. Cruz if Mr. Cruz abandoned plans to campaign in New Mexico and Oregon. (Mr. Kasich instantly complicated matters by urging Indiana voters on Monday to support him, anyway.)

“I recognize that the media is all eager to talk about an alliance. There is no alliance,” Mr. Cruz said. “Kasich and I made a determination where to focus our energies, where to focus our assets, where to focus our resources.”

While he said the two agreed that Donald J. Trump would be a disastrous Republican nominee, Mr. Cruz cast Mr. Kasich’s participation in the gambit as something less than altruistic.

“John Kasich made the decision, in his own political self-interest, to withdraw from Indiana and to go compete elsewhere,” Mr. Cruz said, while continuing to campaign in the state six days before its primary. “And that was a perfectly reasonable decision.”

Mr. Cruz did not answer questions about whether he was similarly pulling out of Oregon, which votes on May 17, or New Mexico, which votes on June 7.

Minutes later, taking the stage at a convention hall, Mr. Cruz told voters that Mr. Kasich had no path to victory.

“John Kasich has pulled out,” he said, omitting any further context. “He’s withdrawn from the state of Indiana.”

The Kasich campaign did not immediately respond to a message seeking comment.

But as Mr. Cruz spoke, Mr. Kasich’s chief strategist, John Weaver, tapped out a semicryptic message on Twitter: “I can’t stand liars.”

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