Wonder if he had a hand in creating this situation that he will enrich himself in.
The market opening has been created by mistakes by the major players in this market, Ambac and the like. They had an excellent business insuring this paper, with very low losses and large savings to the localities involved. But they went after the growing market for mortgage insurance in the last five years, as the same companies. They only have so much capital, and they effectively mixed the risks by pledging their own credit in both places.
Now that they are losing badly in mortgages, and their stocks have lost 40% of their value or more, and the credit ratings of these insurers are under review for downgrading (and some already have been), Buffet's underwriters can just step in. He was not involved in the housing stuff so Berkshire's credit remains pristine.
The previous players should never have mixed the low risk business of municipal underwriting, with the higher risk one of mortgage underwriting. But they did not see the riskiness of the second of those, only a chance to write more business. Buffett is simply filling the gap that mistake created and taking away the business they imperiled by their own overreaching.
Buffett can be as wrong as you please on other matters, but here he is performing a public service and providing useful financial services at a time when the usual providers of it as stressed, in classic "white knight" fashion. He will get a good deal out of it. He deserves it.