I’ve seen him described as pro-abortion—so perhaps he’s squishy.
Anyone who turns pro-gay-marriage will eventually turn pro-abortion.
Anyone who turns pro-abortion will eventually turn pro-gay-marriage.
I don’t believe Portman is pro-abortion, and your statements are generalizing, not true at all.
Perhaps you’ve seen Portman described as pro-abortion because some people choose to defame those that have disappointed them on other issues. Rob Portman has had a perfect pro-life voting record since he was first elected to the House in the 1990s: http://nrlc.capwiz.com/bio/id/460
As for your theory that everyone that turns pro-abortion eventually will turn pro-same-sex marriage, and that everyone that turns pro-same-sex marriage eventually will turn pro-abortion, I disagree. They are separate issues with completely different social and philosophical underpinnings. I can think of several principled pro-lifers that will not deviate from that position even though they have caved to the sodomofascists on the definition of marriage.
As for Portman, he turned his back on marriage because his son came out as gay and complained to him, and he thought that he was being a good father by supporting same-sex marriage. It was a one-off thing, not a conversion to liberalism.