Yes, it's possible. Without starting a big debate over "tap rules", you should wire the fixture in #12 wire. The factory wiring within the fixture is satisfactory for the "load served". THe switch may be rated 15 amp, as it is only "switching" the 65 watt load of the fixture.
Please substitute the word "luminare" for "fixture" within the above comments, to be politically correct. It's hard for us guys that have been around for a while to "change our ways" on some subjects.
AS always, if you personally are "not qualified" to perform electrical work, you should consider locating a local electrical contractor/electrician. Residential voltages can cause serious bodily harm, and death as a worst case scenario.
[This message has been edited by HotLine1 (edited 09-26-2003).]