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.
(..) Gandalf the Grey. That was my name. Gandalf. I am Gandalf the White. And I come back to you now... ...at the turn of the tide. One stage of your journey is over. Another begins. War has come to Rohan. We must ride to Edoras with all speed. That is one of the Mearas... (..)2002 The Lord of the Rings: The Two Towers