Texas Gov. Greg Abbott bluntly told President Biden in a letter Monday he's not backing away from his aggressive border security efforts despite the U.S. Justice Department's threat last week to sue on grounds that the state is usurping federal authority. "You must fully enforce the laws of the United States that prohibit illegal immigration between ports of entry," the Republican governor told the Democratic president. "In the meantime, Texas will fully utilize its constitutional authority to deal with the crisis you have caused. Texas will see you in court, Mr. President.”