It's cheap populist politics at the end of the day. They wouldn't dare touch it with an American manufacturer.
That's because now the US government is now a major shareholder. Going after Toyota could be interpreted as a way to help their investments.
Oh please. Bush back in 2006 saying the Big 3 didn't make vehicles the public wanted and said he wouldn't help them( though he eventually did back in 2008, but according to Cheney I believe he did it so it would be one less thing he would be responsible for).
The Big 3 have been under the scrutiny of our government plenty of times. Most recent is back in 2008 when Congress grilled them when the CEO's went to ask for a loan. Even when our government took a 60% ownership of GM, they didn't hesitate to criticize its mismanagement. They stated GM's handling of its finances were the worst they have ever seen.
Which is why the US government could be accused of now trying to protect its ownership stake.
Just thinking out loud...