Here is a video, showing a number of Russian opposition activists visiting U.S. embassy before Russian presidential elections:
On way back they all say a completely identical phrase to the camera (actually held by an amauter) "You are Surkov's propaganda" (Surkov is a Putin's deputy)
It is known that U.S. openly supports Russian opposition.
Thus my question is whether it is permitted in the US to spend the taxpayers' money to support pro-US parties in foreign countries?
If so, whether it is permitted for a currently ruling party in the US to spend the state money to support their own political agenda abroad?
How this was arranged formerly and whether there were any political or judicial controversies about this issue?