Final answer:
The Texas governor acts as the commander-in-chief of the Texas military forces unless they are called into the actual service of the United States, at which point the president assumes command.
Step-by-step explanation:
The governor of Texas serves as commander-in-chief of the Texas military forces, except when they are called into the actual service of the United States. This means that if the president, who is the commander-in-chief of the military forces of the entire United States, including the National Guard and reserves, federalizes the Texas military forces in a time of war or national emergency, the command authority is transferred from the Texas governor to the president.
The powers of the president as commander-in-chief are outlined in Section 2 of the U.S. Constitution, which grants them significant authority in matters of national defense and foreign policy. The president can call upon the militia, which includes the National Guard, to serve at the federal level as a part of the nation's armed forces. They also have the authority to grant reprieves and pardons and to appoint various government officials with the Senate's advice and consent.