The Pennsylvania Republican said Roberts' "extraordinary academic record" and "illustrious career" had made him well qualified to lead the Supreme Court, the report said.
Specter told the Senate he was reassured by Roberts' statements that the Constitution is a document "intended to apply in a meaningful way down through the ages."
Specter said Roberts also had strongly affirmed his belief in the right to privacy, which laid the groundwork for the 1972 Roe vs. Wade decision legalizing the right to abortion. Roberts also supported the importance of judicial precedent, making it less likely that he'd try to overturn Roe, the report said.
Most of the Senate's 55 Republicans are expected to vote for Roberts, but Specter is among the first to formally announce his position, the newspaper said. So far, no Democrat has publicly announced opposition to Roberts.