Obama was the most liberal Senator of 2007, Clinton was the 16th most liberal.
The last three years, Obama as placed 16th, 10th and 1st.
Clinton’s record since she entered the Senate has been between 8th and 34th.
http://nj.nationaljournal.com/voteratings/
Overall in NJ’s 2007 ratings, Obama voted the liberal position on 65 of the 66 key votes on which he voted; Clinton voted the liberal position 77 of 82 times. Obama garnered perfect liberal scores in both the economic and social categories. His score in the foreign-policy category was nearly perfect, pulled down a notch by the only conservative vote that he cast in the ratings, on a Republican-sponsored resolution expressing the sense of Congress that funding should not be cut off for U.S. troops in harm’s way. The Senate passed the resolution 82-16 with the support of both Obama and Clinton. The 16 opponents included mostly liberals, such as Sens. Russell Feingold, D-Wis., and Sanders.
Clinton took the conservative position four other times in NJ’s 2007 ratings. (See how Obama and Clinton voted in the three issue categories in this PDF.) The one that registered the loudest on the campaign trail was a vote that she cast in favor of an amendment sponsored by Sens. Joe Lieberman, ID-Conn., and Jon Kyl, R-Ariz., that called on the Bush administration to reduce Iranian influence on Iraq and to designate the Iranian revolutionary guard as a terrorist organization. The “sense of the Senate” amendment was approved 76-22.