U.S. Sen. Ted Cruz was crisscrossing Texas this week, meeting with constituents in Houston, El Paso, San Antonio, Laredo, Amarillo, Lubbock, Dallas and Tyler. It wasn’t how Cruz had once hoped to be spending the second week of August, when, had things gone his way, he might have been hopscotching battleground states as the Republican nominee for president. Instead, it was Donald Trump with rallies and speeches in North Carolina, Virginia, Florida and Pennsylvania — Donald Trump, who Cruz refused to endorse for president in his speech at the Republican National Convention in July, and who, the day after he...