Senator Ted Cruz of Texas, desperate to alter the course of a presidential primary fight in which Donald J. Trump is closing in on victory, will announce Wednesday afternoon that Carly Fiorina will be his running mate if he wins the Republican nomination, two campaign advisers confirmed.
The move, a day after Mr. Trump scored unexpectedly wide victory margins in sweeping five East Coast states, amounts to the grandest diversionary tactic a presidential candidate can stage — or at least the grandest one available to a candidate trailing by about 400 delegates who failed to win more than 25 percent of the vote in any state on Tuesday.
Mr. Cruz’s decision to rush out a vice-presidential pick before next week’s primary in Indiana, which is becoming make-or-break for his candidacy, was the political equivalent of a student pulling a fire alarm to avoid an exam: It was certain to draw attention and carried the possibility of meeting its immediate goal, but seemed unlikely to forestall the eventual reckoning.
Still, for Mr. Cruz, it could serve to shift the focus away from Mr. Trump’s success and from his own wheezing alliance with Gov. John Kasich of Ohio, who agreed to clear out of Indiana if Mr. Cruz withdrew from competition in Oregon and New Mexico. And since endorsing Mr. Cruz last month, Mrs. Fiorina, the former presidential candidate and Hewlett-Packard chief executive, has proved to be an eager surrogate, attacking both Mr. Trump and Hillary Clinton with zeal.