"If you get too emotional, that undercuts you. A man can cry — but a woman, that's a different kind of dynamic."
I'm an emotional person myself (I know, I know, that surprises you), and I grew up in a family with men who weren't afraid to cry. (Although sometimes this condition was referred to as "sweaty eyes.") To me, tearing up doesn't show weakness, but compassion. (Blubbering, now, is a different story, and that's what generally happens to me, not just a few dignified tears.) I have often thought that it must be difficult to be male in US society, when there is so much confusion about how much emotion is OK. But Hillary Clinton's comment makes a strange kind of sense, too; if you're competing in a man's world, anything that can be construed as weakness is a risk. And I have a policy of trying not to cry in front of my students (though I may tear up from time to time, I'm not telling). There are way more of them than there are of me, and I do feel weakened by my tears, even though I don't perceive others as weak for crying.
I learned in the earthquake that there are people you want on your side when the world is falling apart because they know just what to do. Until you've been tested in a major catastrophe, you just don't know if you are that kind of person. What I want in a leader is someone who can remain completely calm in a crisis. Maybe he or she will cry later, remembering what happened, but at that moment there is an ability to compartmentalize, to do what needs to be done, and to save the falling apart for another time. But disaster is not the kind of thing you can practice for. People tearing up over their cancer or an experience with a child are not necessarily showing that they don't have that kind of sang-froid. Maybe they had it when they needed it. And anyway, a personal, relational experience will hit differently from a national emergency where many people's lives are at stake.
So, I don't mind political candidates expressing emotion. I join right in; when other people cry, so do I. But if you want to be president, I hope you can set emotion aside when you have to.