Of course, as the piece points out, the ploy is designed to lure back Catholics leery about the Dems' position on life issues. But there's also a subtext.
Offering a prominent platform to a pro-lifer is another sign of nervousness in Obama ranks over the sheer extremism of Barack's stand on abortion issues -- from opposing a state version of the Born Alive Infant Protection Act (see link immediately above for the whole sordid story) to his wife's 2004 fundraising letter openly defending the "so-called partial birth abortion ban." (Wouldn't it be interesting to see if -- like her husband when it comes to guns -- she's now changed her position on constitutionality of the ban, now that the Supremes have upheld it?)
Even his supporters realize Barack is vulnerable on the abortion issue. And it's not clear to me that a speech by Robert Casey is going to be enough to satisfy the very legitimate concerns people have abotu Barack's extreme pro-abortion positions.