The Wall Street Journal’s Mary Kissel tweets: 
Blocking Hagel sets a bad precedent & lets Obama label the GOP obstructionist. And what happens when the Rs take back the White House?
[More on the Hagel non-filibuster here]

Do precedents matter? Does my behavior today shape the future actions of others?  
Sure, there are plenty of situations where a decision today causes, shapes the future: If I eat the last coconut on the deserted island I’m done eating coconuts.  But does my random act of kindness generate future acts of kindness?  Does today’s cruelty cause future cruelty?  
Kissel’s idea, widely believed, is a story of multiple equilibria where one can get to a better long- term equilibrium if only we would, today, use our free will for good rather than evil.  
I suspect that the more likely reason that cruelty predicts cruelty and kindness kindness is because the outcomes–cruel or kind–are driven by deeper causes.  Deeper causes that, in the case of politics, we can sum up under the heading “The Internet“. The political splintering caused by the rise of social media means that politicians face a new set of forces shaping their behavior, forces likely to be with us for a long time.  Those forces pushes politicians to new equilibrium behavior, with less (if any) room for individual acts of kindness to shape the future.  
Think of it this way: In a normal competitive market, if a supplier one week decides to be “nice” and cut her price, we all know that has no long-term effect on the market.  Her week of kindness means she sells a lot, but after her one-person jubilee the market goes back to the normal supply and demand equilibrium.  Her kindness gets remembered on a blog or two but is forgotten by the invisible hand.  
Do you think the actions of elite politicians are driven by forces as strong, as deterministic, as in a competitive market?  If so, then a week of kindness toward Chuck Hagel will have no effect on the political system. 
I’m no great believer in free will–the neuroscientific evidence for it isn’t great–but even if I were, I’d still have to wonder whether individual acts of choice can drive long-term outcomes.  In competitive markets and perhaps in politics, the answer is no.