Support has declined and opposition has increased. I don't think there's much of a disconnect here though, since it doesn't seem there are many people with strong opinions counter to what Congress chose to do.
"Not Sure" != "ambivalent". It's a mistake to lump "Not Sure" and "Opposed" together and declare a majority, as the group as a while does not represent a specific stance. Any attempt at nuance for either side gets bucketed into the largest category.
That group seems like the most interesting question... what sub groups do they fall into.
Anytime there are such large numbers of "undecideds" it's likely they are low-information, and an opportunity for Trump (or any unscrupulous politician, but really, Trump) to lie to them and turn them to whatever side they wish.
