Police tangled with student demonstrators in Texas and California while new encampments sprouted Wednesday at Harvard and other colleges as school leaders sought ways to defuse a growing wave of pro-Palestinian protests. At the University of Texas at Austin, dozens of local police and state troopers formed a line to prevent students from marching through the campus, eventually clashing with the protesters and detaining multiple people. And at the University of Southern California, police removed several tents, then got into a back-and-forth tugging match with protesters over tents before falling back. Harvard University in Massachusetts had sought to stay ahead...