Politically, she tends to 'go against the tide' on her college campus. [=she tends to have different political opinions than most people on her college campus]
He became involved in social issues at the 'high tide' of the civil rights movement. [=at the most active and important time of the civil rights movement]
The team was on a losing streak, but then 'the tide turned' [=their luck changed] and they went on to win the championship.
(..) ...to when we were desperately fighting to stay alive... ...and we were nearly losing the battle. And then Thorin turns the tide of the battle... ...and we rally and we defeat the Orcs. I remember having a big shield. Every single time, I managed to bounce this shield off of an Orc... (..)2012 The Hobbit: An Unexpected Journey