affect: To have an influence on or cause a change in.

“ Intense lobbying affected the vote.”

Note: Affect and effect are commonly confused, though they have no meanings in common. Effect is more commonly used as a noun: “When the witness appeared on the last day of the trial, the effect was that judge granted a continuance.” So, when you affect a situation, you have an effect on it. However, effect can also be used as a verb meaning to bring about, create or execute: “The newly merged company tried to effect a change in the group’s hiring practices.”