When will the first woman serve as President Pro Tempore?

[Mr. Morden]

President Pro Temp is decided by seniority, not age.  Mikulski is the most senior woman in the Senate, and she's 75 years old.  The Democrats more senior than her and their ages:

Inouye 87
Leahy 72
Baucus 70
Levin 77
Bingaman 68
Kerry 68
Harkin 72
Rockefeller 74

Bingaman is retiring this year, and Kerry is widely considered the frontrunner to be appointed by Obama as Secretary of State in his second term if Obama's reelected.  If that happens, then Mikulski would just have to outlast the men who're now in their early 70s, like Leahy, Baucus, and Rockefeller.  Certainly *possible*, but not a sure thing.  It's unlikely to happen until at least 2025 or so.  And even then, you'd need a Dem majority for her to be the President Pro Temp.

If Mikulski doesn't pull it off, then the most likely Democratic woman to become the first female President Pro Temp is Patty Murray, who's 61 years old, and is younger than every single Senator who's more senior than her.  But she likely wouldn't become President Pro Temp for at least 20 years.  And again, she would need a Dem majority.

The most senior Republican woman who isn't retiring this year is Susan Collins, who's 59 years old, and also younger than every single senator who's more senior than her.  So she also has a very good chance of eventually becoming President Pro Temp, assuming she doesn't get primaried out of office or something.

On the other offices you mentioned, I'd assume that there's a better than 50/50 chance that there'll be a female Secretary of the Treasury within the next 10 years or so.  Probably longer than that for SecDef.

For the presidency and the vice presidency......my assumption is that there's a >95% chance that the 2016 Democratic ticket has a woman on it.  Whether it's as the presidential or vice presidential candidate probably depends on whether or not Clinton runs.  In fact, my assumption is that virtually every election from now on will see the Dems nominate a woman for either prez or VP.  On the GOP side, starting from around 2020 (if not earlier), they'll start having either a woman or racial minority paired with a while male in every presidential election.  Though how often that'll be a woman rather than a male racial minority, I don't know.