Why does Ecuador even want to stand its ground on this? Why do they want to harbor Assange in the first place? Seems silly to escalate this to the national level when they don't seem to benefit from it in any material or practical sense.
South American countries tend to lurch from right to left and back. Currently Ecuador has elected to be governed by their anti-American leftist party. I would be shocked if they didn't grant Assange asylum just for the sake of pretending to save Assange from the US, if for no better reason.
I'm no pro in politics but what I have read Ecuador has pretty strong relationship with Venezuela. And at least the later one is happy to get USA "angry" when possible.