[bcsco]

How did someone with such a thin resume become a United States senator

It's called the Chicago Machine.

much less the presumtive nominee for president of the largest political party in the world's only superpower?

It's called Democrat voters.

[Clock King]

...the Chicago Machine.

[Foolsgold]

[semantic]

It's called the Chicago Machine.

I beg to disagree - the real reason is exactly as Ferraro implied: it's due to affirmative action.