He’ll have plenty of time for vacations when his one term is up. Plenty of time.
One robin does not make a spring, and one anti-Obama joke doesn't make Letterman palatable to conservatives. Still, as Lao Tzu said, a journey of a thousand miles begins with a single step. Letterman has taken a step.
My source for the Letterman quote is The Wall Street Journal; if you go here you can also view the video.