Are DDOS attacks after a political victory a threat?

I noticed tonight that Newt Gingrich kept mentioning his website. Without explicitly saying it, I assumed it was to get people to go there and donate. Could a DDOS over the period of time after a political victory shut down the ability to make donations, or is it not practicable. I'm certainly not endorsing the idea, but is there a way for political candidates protect against this type of attack overnight?