They considered Wisconsin, Michigan, and Pennsylvania in the bag for them. Her campaign invested little time or money in those states. They did not even do much internal polling. They concentrated on the the swing states. They never knew that Wisconsin, Michigan and Pennsylvania were swing states.
Florida was a swing state and her campaign invested much in that state. When Florida was called for Trump, I knew she was doomed even before Wisconsin, Michigan and Pennsylvania were called for Trump.
Election Night - SNL
https://www.youtube.com/watch?v=SHG0ezLiVGc
They did know they were swing states, they thought they were going to steal them like they did the last two elections.
We in WI finally got the voter ID stuff changed and that took a big dent out of the bussed in Illinois folks democrats couldn’t bring in, nearly as easily as the last elections.
Further the democrat base here was not nearly as amped up to vote for Hillary as they were for Obama.
Combine it with such hatred for what Obama/democrats did the last 8 years, and that Walker has actually done good things here without raising taxes, and that the entire state govt has shifted hard to the right, and they totally blew it here.