Obama was so intent on protecting our borders from illegal aliens, that he made it impossible to renew your drivers license on-line, you have to appear in person with your birth certificate, some bills in your name, a social security card, another gov't ID (GWL will work), to prove that you are not trying to sneek into the US of A.
Above info about GWL is correct. I let mine expire, and have to through the whole process. No big deal really, mostly a PITA.