Democratic Rep. Dan Boren, Oklahoma's only Democratic member of the congressional delegation, has refused to endorse Sen. Barack Obama for presidential office.

However Boren has said the Illinois Senator will have his vote both at the Democratic convention in Denver in August and in November on election day.

Calling Obama "the most liberal senator in Congress", Boren criticised his record on working with Republicans saying "it does not reflect working in a bipartisan fashion" and has joined Florida Rep. Tim Mahoney in refusing to endorse the presumptive Democratic nominee.

Image: Official picture of Dan Boren. Credit: Public Domain