Final answer:
The Texas government collapsed after the end of the Civil War as the Confederate defeat led to the governor fleeing to Mexico and the disbanding of the state government.
Step-by-step explanation:
The Texas government collapsed at the end of the Civil War as a direct result of the defeat of the Confederate States of America, to which Texas belonged. When General Lee surrendered at Appomattox Court House in Virginia to Union General Grant on April 9, 1865, it signaled the end of the Confederacy.
Texas, being one of the seceded states, found its government effectively nullified. The Confederate governor, Pendleton Murrah, fled to Mexico, avoiding capture by Union forces.
This event emphasized the dominance of the national government over the states, particularly in areas such as the legality of secession and the enforcement of national law. With no functional government left in place, Texas underwent a period of military occupation and reconstruction much like other former Confederate states.