The only question then is: was defunding ObamaCare within their power? Most people outside the Tea Party recognized that defunding ObamaCare was also beyond their power -- and events confirmed that.
It was virtually inconceivable from the outset that the Tea Party could force the Democrats who controlled the Senate to pass the defunding bill, even if the Tea Party had the complete support of all Republican Senators -- much less pass it with a majority large enough to override President Obama's certain veto.
Therefore was the Tea Party-led attempt to defund ObamaCare something that met Burke's standard of a "rational endeavour"?
With the chances of making a dent in ObamaCare by trying to defund it being virtually zero, and the Republican Party's chances of gaining power in either the 2014 or 2016 elections being reduced by the public's backlash against that futile attempt, there was virtually nothing to gain politically and much to lose.
However difficult it might be to repeal ObamaCare after it gets up and running, the odds against repeal, after the 2014 and 2016 elections, are certainly no worse than the odds against defunding it in 2013. Winning those elections would improve the odds.
If the Tea Party made a tactical mistake, that is not necessarily fatal in politics. People can even learn from their mistakes -- but only if they admit to themselves that they were mistaken. Whether the Tea Party can do that may determine not only its fate but the fate of an America that still needs the principles that brought Tea Party members together in the first place.