TXU’s shareholders have spoken, and unlike some debt investors, they don’t think a leveraged buyout is such a bad idea.

After winning shareholder approval on Friday for the $32 billion buyout of Texas power company TXU Corp, only the debt markets - and one regulatory approval - stand between Kohlberg Kravis Roberts & Co and TPG Capital finally getting a big power deal to the finish line.

That’s a long way from KKR’s and TPG’s forays into Arizona and Oregon. KKR, shot down nearly three years ago by Arizona regulators when it tried to buy Unisource with a group of investors, and TPG Capital, which fell to the Oregon regulators only a few months later in its attempt to buy Portland General, might actually have learned from their mistakes.

The private equity firms spent the first half of this year maneuvering their way through Texas’ regulators, environmental activists and legislators during the spring. This summer they hit the road to talk to investors as they faced opposition from their largest holder.

For a power deal, it’s all been done unusually fast. For instance, Exelon and Public Service Enterprise Group had been working on their deal for over a year and FPL Group and Constellation on theirs for almost a year when they finally decided to call it quits (again, because of issues with state regulators).

And now, what’s left to navigate is something that KKR and TPG probably had not calculated into their model early this year - the effect of the collapse of the sub-prime mortgage market on the broader markets and demand for their own debt.

First Data Corp is taking the brunt of the market’s worries right now. Depending on how the sale of its debt goes, KKR and TPG could find themselves next up fighting with the banks over the terms of their debt to try to make it more attractive to buyers. The TXU deal is expected to close in October.

That’s one battle they couldn’t really have prepared for last spring.