Boehner's plan is a nonstarter in the White House and the Senate because it does not lift the debt ceiling unconditionally until 2013. Yet, even his plan loses 100 Tea Party Republican Congresspeople. Therefore, he is a man without a coalition that he can deliver, a man without a party backing him. And he must have numerous the votes of numerous Democratic Congresspeople. This is the only way that he can get a bill passed. If he doesn't, it hurts the national brand of his party by causing the country to default.
Since perhaps most of the support must come from Democratic Congresspeople who are willing to do the right thing and raise the debt ceiling (and there are just not enough votes to be had even given his latest extremist offer among Republicans - and he surely knows anything more extreme won't pass the other chamber and will be vetoed) , his only choice is to offer a plan that can get strong support from Democrats, probably that is where most of his votes must come from.
In any attempt to win most of his votes from Democratic Congresspeople, he must design a package that they could vote for. What passes the House with Democratic votes can pass the Senate. On the other hand, what passes the House with virtually only Republican votes cannot pass the Senate or the White House.
It is possible to get something to pass the House with mostly Democratic votes which also passes the Senate and the President would either sign or allow to become law in 10 days. It is increasingly clear that this is the approach that he must take. He has already rightly lost the P. R. battle. And the consequences of default are enormous. He and his party, nationally, will bear the majority of the brunt of the wrath of the voters if this is not passed. And if he knows the economic consequences if he does not get something passed. For these reasons, his only option is to design a debt ceiling bill that will win Democratic support, getting most of his votes from our side of the aisle.
Between the growing realization of this and the pressure from Wall Street and the rest of the world, he may choose to take the only option open (above) in order to avoid catastrophe for the country, the world, and the brand of his national party.