Three days after headlining the Obama campaign's roll-out of GOP supporters, former Sen. Lincoln Chafee (R-R.I.) announced today that he will join the board of directors for NARAL Pro-Choice America this fall.

Chafee, now an independent, said abortion rights provide a stark difference between Barack ObamaBarack Hussein ObamaAll five living former presidents to attend hurricane relief concert Overnight Health Care: Schumer calls for tying ObamaCare fix to children's health insurance | Puerto Rico's water woes worsen | Dems plead for nursing home residents' right to sue Interior moves to delay Obama’s methane leak rule MORE and John McCainJohn Sidney McCainRubio asks Army to kick out West Point grad with pro-communist posts The VA's woes cannot be pinned on any singular administration Overnight Defense: Mattis offers support for Iran deal | McCain blocks nominees over Afghanistan strategy | Trump, Tillerson spilt raises new questions about N. Korea policy MORE, blasting the Arizona Republican for not supporting them at a federal level. Chafee endorsed Obama in February.

"I have always said that being pro-choice is a mainstream conservative value," Chafee said. "It is unfortunate that Sen. McCain does not share the view of many mainstream Republicans that privacy and freedom from government interference in personal decisions is a core value."

"This is one of the clearest differences between Sen. Obama and Sen. John McCain--and it is a difference that matters to voters, including pro-choice Independent and Republican women," Chafee said.

McCain yesterday floated the possibility of tapping a pro-abortion-rights running mate in an interview with The Weekly Standard. McCain has said he would like to see Roe v. Wade overturned, giving states authority over abortion rights, and for the U.S. to work toward ending abortion as a practice.