What might the word "affirming" mean here

To affirm something is to give it a big "YES" or to confirm that it is true.

Explanation:  

The verb affirm means to answer positively, but it has a more weighty meaning in legal circles. People are asked to swear an oath or affirm that they will tell the truth in a court of law.

for the united states of america, 1945 to 1964 was a time of high economic growth and general prosperity. it was also a time of confrontation as the capitalist united states and its allies politically opposed the soviet union and other communist countries; the cold war had begun.

explanation:

a yes vote means: the legislature, with a two-thirds vote, could change daylight saving time if the change is allowed by the federal government. absent any legislative change, california would maintain its current daylight saving time period