This Washington Post blog was pointed out as an instance of media bias by Newsbusters:WashPost: Republican Spoke 'In Anger,' Democrat Had 'Fervor of a Preacher'.

They give this as an example of the implicit bias:

The comments infuriated many Democrats, who rose to speak for the bill. The most eloquent was Del. Melvin L. Stukes (D-Baltimore), who spoke with the fervor of a preacher. He compared opposition to undocumented students with the 1700s view of slaves as less than human.

"Do I need anyone to remind me of the mind-set that existed then and still exists today, that some people were considered three-fifths of a human being?" Stukes asked, his voice rising. "Are we still saying that some people are less than whole? I don't think so."[House Heats Up Over Bill to Give Illegal Immigrants In-State Tuition]

The three-fifths thing has always annoyed me. It was the slaveowners who wanted slaves counted, for purposes of electoral apportionment, as equal to free men. It was the free states that objected. Slaves would have been better off being counted as zero for electoral purposes, since it was their owners who had the vote, and who would benefit by having extra pro-slavery congressmen.

But as of 2007, an illegal alien is not counted as three-fifths of citizen, for purposes of electoral apportionment. Nor as zero, which is what you might expect the Census to do. For purposes of electoral apportionment, he's counted exactly the same as if he were a citizen. See the first thing I ever wrote for VDARE.com, more than six years ago:Immigration’s Rotten Borough dynamic...