Final answer:
The Texas v. White case resulted in the affirmation that states could not legally secede from the Union, thereby invalidating acts done by Confederate states during the Civil War.
Step-by-step explanation:
One of the consequences of Texas v. White et al. 1869 was the Supreme Court's declaration that secession was not legal, and thus the ordinances of secession passed by the Confederate states were null. The case reaffirmed the principle that the Constitution established an indissoluble union from which no state can secede. This decision had significant implications for the Reconstruction era, effectively asserting that all acts done by the seceding states during the Civil War were without legal validity.