For example, lets take our inept ex-secretary of state Madelaine Albright. In 1991 she was against war with Iraq and fervently against US forces going into Baghdad and deposing Saddam. Her statements are recorded in print and on video. In 1998, she was for attacking and deposing Saddam, but better yet, she criticized the previous adminstration for not taking Saddam out, while they had the chance, contradicting her earlier statements. Presently, in 2002, she is once again against military action in Iraq, once again contradicting herself.
To paraphrase "Love Story" - Love means never having to say you're sorry - Being Liberal means never having to say you're wrong.
Besides, liberalism is all about feelings and intentions, not facts and results. Who's to say that someone else's "feelings" are wrong?