Josh Boak: Republican control of the House has left Democrats with the choice of either agreeing to continue the lower rates for wealthier Americans, or watching as they all expire and the country plunges back into a downturn. The Democrats would now prefer to hazard the hard landing. Their gambit depends entirely on the danger of a financial shock severe enough to force GOP lawmakers to back down, yet not so overpowering that it triggers a vicious slump…..