Why do we have an ineffective political system?

I've wondered for a while why the system is the way it is: an have never seen a good reason: so here is a question: why did the founders design congress to be re-elected every two years rather than over a longer period? Was there some different political dynamic which meant that things could happen faster then than they do now?
Other countries had much longer political terms: presumably the short house term was a deliberate choice. But in the context of getting unpleasant things done, the sort of "hold your nose and vote for it because it is the right thing to do" bill, it might be much better for the country if ones elected officials were less concerned about the vote a few months from now.

Of course, this is all exacerbated by the constant news cycle and the need to be continually begging for money.

Yours, intrigued,
N