The first bullets struck El Paso's city hall at the end of a work day. The next ones hit a university building and closed a major highway. Shootouts in the drug war along the U.S.-Mexico border are sending bullets whizzing across the Rio Grande into one of the nation's safest cities, where authorities worry it's only a matter of time before someone gets hurt or killed. At least eight bullets have been fired into El Paso in the last few weeks from the rising violence in Ciudad Juarez, Mexico, one of the world's most dangerous places. And all American police...