(CNN) - Meghan McCain - whose departure from conservative orthodoxy on some issues has put her at odds with some in the GOP base - said Thursday that former moderate Republican Sen. Arlen Specter had "let us down" by leaving the party.
"Let me be clear: I have a lot of respect for Sen. Specter," said McCain, in her latest blog post for the Daily Beast. "But I also can't help but feel like he's let us down.
"I'm sure this was a long, hard decision. The polls were looking very bleak in his primary contest. His probable opponent was nearly 20 points ahead in many polls. And I understand how he's been made to feel like an outcast by a small, vocal group. Still, this was an opportunity for Specter to hold his ground and set an example for progressive-minded Republicans trying to overcome one of their biggest obstacles: winning the party primaries....
"We need courageous Republicans more than ever. And this week, Sen. Specter turned his back."
Earlier this week, conservative radio talk show host Rush Limbaugh suggested that McCain leave the party with Specter. "A lot of people say, 'Well, Specter, take [Sen. John] McCain with you. And his daughter [Meghan]. Take McCain and his daughter with you if you're gonna…" he told listeners Tuesday.