Yes, It is
No, it is not
Help fight Zika, TB, HIV/AIDs and water pollution by donating your CPU's excess processing time to computing-based scientific research.
But even if it were a question of party preferences, the invitation by the Legislative would not be a question of US sovereignty as much as constitutional precedent.
Killing one person is murder, killing 100,000 is foreign policy
I think that any country that receives substantial US aid should require their head of government to make a speech before Congress each year.