How can the Senate apologize "for slavery", exactly?
Were they supposed to amend the constitution? Challenge the Dred Scott decision? Trample the Federalism that supported Jim Crow?
It would have been interesting, and perhaps timely, if this Senate had the courage to apologize for not doing more to stop lynching, at the Federal level... Too close to home, for that?
In the past 20 years, the Senate has done nothing at the Federal level to stem the tide of physical violence on gay citizens. One day, there will be an apology for that, maybe even in Trent Lott or Orrin Hatch's lifetime (one can hope).
[Special note: it was a voice vote, not a roll call. Make of that what you will. Lions in the Senate, today? Well, it seems there are few current day versions of Senator Sumner...]
Update: Other things the Senate could apologize for include not putting Social Security receipts into a "lock box", at least to some degree... other candidates include failing to get an international agreement on emissions done. The list goes on.