You measure my life in hours and I serve you by expiring. I'm quick when I'm thin and slow when I'm fat. The wind is my enemy.

A candle

Explanation:

As the flame burns, the candle slowly starts to deteriorate, that's how it serves you by expiring. The wind is the enemy because it'll blow the candle out.

the framers of the constitution insisted that federal judges be nominated instead of elected due to their desire to have judges above the shifting whims of the masses.

the hope, whether achieved or not, was that federal judges would only be beholden to the law and that by not having judges be elected, they would be protected if that law dictated an outcome that ran counter to popular opinion.

a physical change is being made.