The reason is pretty simple. A fiscal conservative puts living within one’s means as the core priority; the current GOP believes that defunding the government should be the core priority. As British chancellor George Osborne has noted, the Tories want to keep taxes as low as possible and government as modest as possible within a balanced budget; the Republicans want to keep taxes as low as possible and government as modest as possible, even if this means vast deficits, or default, within a divided government. No fiscal conservative would or could defend the continuation of the ruinous Bush tax cuts through two wars and a massive new GOP entitlement, Medicare D, let alone now when the debt crisis is this grave. Only those who believe “deficits don’t matter” would. And they have. More to the point, their only true line in the sand is preservation of those tax cuts, or rather preservation of revenues at their current paltry levels. Bruce Bartlett, the principled conservative ostracized by the GOP establishment because of his criticism of the big spending Bush years, notes the following:

Revenue has been below 15 percent of G.D.P. since 2009, and the last time we had three years in a row when revenue as a share of G.D.P. was that low was 1941 to 1943.

Revenue has averaged 18 percent of G.D.P. since 1970 and a little more than that in the postwar era. At a similar stage in previous business cycles, two years past the trough, revenue was considerably higher: 18 percent of G.D.P. in 1977 after the 1973-75 recession; 17.3 percent of G.D.P. in 1984 after the 1981-82 recession, and 17.5 percent of G.D.P. in 1993 after the 1990-91 recession. Revenue was markedly lower, however, at this point after the 2001 recession and was just 16.2 percent of G.D.P. in 2003.

And when simple math will tell you that revenues will have to increase because of demographic pressures, even if healthcare costs were to be controlled, the refusal to contemplate any revenue increases is simply dogma at the expense of reality. The Bush tax cuts were the economic version of the $4 trillion wars he failed to win:

According to a recent C.B.O. report, [the Bush tax cuts] reduced revenue by at least $2.9 trillion below what it otherwise would have been between 2001 and 2011. Slower-than-expected growth reduced revenue by another $3.5 trillion. Spending was $5.6 trillion higher than the C.B.O. anticipated for a total fiscal turnaround of $12 trillion. That is how a $6 trillion projected surplus turned into a cumulative deficit of $6 trillion.

But propagandists like Fox and Instapundit will tell you with a straight face that all this debt is Obama’s fault.