Politcs in a bank

How big of a role do politics play in a bank? Here is my situation, I currently have fixed income summer offers from both Credit Suisse and Morgan Stanley. I have read that Credit Suisse has the stroger fixd income division, but I am drawn to Morgan Stanley because of both the name and the amount of alumnae my school has in FID at the firm. I have been told that having alumnae present offers a level of 'protection,' as there will be a built in network of people to vouch on my behalf (re: offers, bonuses, promotions, etc). I really liked the people/culture at CS, is my alumnae network at MS worth making the decision to go there instead? I know both are great places, and I can't really go wrong, but I'd love to hear if anybody has an opinion on the significance of having an alumnae network/advice about which firm I should pick.

Thanks for the help!