Here is a paragraph from a letter attributed to him.
I am not a lawyer, and cannot claim to be an expert on impeachment. However, based on what I know now, I am not persuaded that it would be appropriate for the House to consider impeaching either the President or Vice President. I opposed going to war in Iraq and disagree with many other policies of the Bush Administration, and will work to change those policies. But at this point I think those changes should come through the normal legislative and political processes, rather than through impeachment.