I've been amazed at the effectiveness with liberals in my network--fair-minded ones--with cartoons from pookie's TOODAY'S TOONS posts. I think at least one couple is very close if not already over the line of voting against all the DIMRATS. And this is a couple known for their liberal attitudes before.
I print off the ones I think would most touch some of them and share them routinely.
It's especially powerful if you can print those which are SOOOOOOO OBVIOUSLY TRUE as to be inescapable. And there are many such.
Your liberals are more sane than the ones I deal with. I live and work in Boston and Cambridge, and it's really amazing how many of the most vociferous libs know NOTHING about the subjects they are so adamantly sure they know the "truth" about.