Jamison Foser has the catch of the day. Here's the RNC's "Political Achievements page, preserved via screen shot just in case they catch up to today's popular rhetoric.
Ok, now scroll down to 1866:
In case that's too small for you to read:
Republicans Passed the 14th Amendment
The 14th Amendment guarantees due process and equal protection of the laws to all citizens. It enshrines in the Constitution provisions of the GOP’s 1866 Civil Rights Act. The original purpose of the 14th Amendment was to defend African-Americans from their Democrat oppressors in the post-Civil War South.
The principal author of the 14th Amendment was U.S. Rep. John Bingham (R-OH). In Congress, all votes in favor of the 14th Amendment were from Republicans, and all votes against it were from Democrats.
In 1868, the Republican Governor of New Jersey vetoed an attempt by the Democrat-controlled legislature to rescind the state's ratification of the 14th Amendment.
Ok, so maybe we do need to go back to 1868 (when the states had all ratified the amendment). But only if that means we get the 1868 Republican party back.