I'm not saying there is any bait and switch going on (I think they're above petty revenge killing), but are there any previous instances where the USG charged someone for a "parking violation" style minor crime to facilitate extradition?
I can't remember the exact case but the U.S. has done this before, IIRC, to Canada. Something about a state extraditing someone for trial in a state court (with a firm agreement to leave off the death penalty) and then the Federal prosecutor swoops in out of nowhere to bring Federal charges that do carry the death penalty.
Edit: Take the above with a grain of salt though, I've spent some time searching for this case (which should be quite famous) and have come up with nothing. The closest was the Söring case where the U.K. has to obtain assurances from both Virginia and the U.S. that the death penalty would not be applied... and it wasn't.
Remember, many of the noisest and most obnoxious people in Congress were elected by mere thousands of voters from American backwaters.
I don't quite follow the argument that those are not senior officials (the speaker of the house definitely qualifies as such, being second in line after the VP to be named President). The fact that people in a position like that are making such calls surely carries some weight with other, less senior officials and might sway a bunch of them to agree with it if only to not be seen as weak.
The thousands of voters from American backwaters collectively seem to command a rather large chunk of the legislative power in the USA.
The numbers scale up a bit for Feinstein, who at least holds statewide office, but the end result is no different.
This isn't a fiddly technical point. The separation of powers between the Legislative and Executive branches is fundamental to our system of government. In cases where dingbat representatives try to rabble-rouse for unwarranted treason charges, you can see why the founders were smart to divest the Legislature of the power to enforce the laws they enact.
This thought also ignores the fact that the USG does not in fact wield the charge of treason casually. John Walker Lindh, for instance, wasn't charged with treason, despite being charged with deliberately planning and conspiring to murder American troops.