Senator Tim Kaine (D., Va.) supports Roe v. Wade. He wants abortion to stay legal even after the twentieth week of pregnancy. When he ran for the Senate, he attacked his Republican opponent for wanting to provide legal protections to unborn children. NARAL, the pro-abortion lobby, has given him a 100 percent rating three years in a row.

But some Democrats don’t want him to be Hillary Clinton’s running mate because he is too moderate on abortion: He has supported partial-birth abortion bans, parental-consent laws, abstinence-education programs, and allowing drivers to select “Choose Life” license plates; and he has said that he is “personally opposed” to abortion. (That list of positions overstates how moderate he is: Like many pro-choice Democrats, he supported a partial-birth abortion ban only if it contained a “health” exception. A leading practitioner of partial-birth abortion noted that the exception would make a ban unenforceable.) It’s a record similar to that of Vice President Joe Biden, who also “personally” believes that unborn children have a right to life that he opposes enforcing. If this issue keeps Kaine off the ticket, it will mean that the Democrats’ pro-abortion litmus test has grown even more stringent.