I know that a consensus is developing on the left, with some folks on the right, that nationalization may be the way to go. So, what's holding things up?
Easy. Logistics. NPR did a story that the FDIC is hiring people as fast as it can, but it still cannot keep up with demand. Taking over a Citi or a BofA would require an amazing number of federal employees to take over such a bank.
So, why keep things quiet in the meantime. Why not acknowledge that nationalization is probable?
Well, you cannot announce nationalization or discuss it ahead of time. Why? Because doing so would cause the value of stock shares to tumble, and people at the bank to start to flee, etc. In other words, having an open dialogue on bank nationalization by the White House would pre-ordain the result of the discussion.
More likely, on some yet to be determined Friday evening, after much secret planning and preparation, including the ongoing hiring of massive amounts of FDIC employees, you quietly take over on a weekend. Also, the government would need to take over other banks in similar financial straits, because taking over Citi would increase fears that BofA would be taken over.
In other words, taking over banks requires a huge FDIC workforce, and if the NPR story is correct, this process is ongoing.
Edit: Here is a story underscoring this point. There is a lack of personnel at the Treasury.
http://www.washingtonpost.com/wp-dyn/content/article/2009/03/01/AR2009030101747.html