Who's a junior senator?

Is bias in the MSM so pervasive now that they not only show bias to the D's, but they are now comfortable revealing their primary picks?

See if you can pick up the subtle bias in Hillary's favor here:

By last night, senior aides to Clinton, who represents New York, and Obama, the junior senator from Illinois, were quarreling on television, their raised voices a measure of how competitive the 2008 presidential campaign has become with more than six months until the first votes are cast.

Catch that? Clinton represents New York, while Obama is just the "junior" senator from Illinois. Why doesn't it say, "Clinton, the junior Senator from New York, and Obama, who represents Illinois......"? Only the "journalist" who wrote the article knows for sure.