Looking good doesn't automatically translate to being good at politics, but it gives your political success a serious boost, and there is a slew of research that backs this up:

https://www.theguardian.com/commentisfree/2012/jun/17/candid... http://www.nytimes.com/2013/11/03/opinion/sunday/health-beau... http://web.mit.edu/polisci/people/faculty/documents/Lawson%2... http://www.macleans.ca/society/science/the-mysterious-power-...