It really doesn't matter what that "issue" for the Left is, because they only use it as a vehicle to further the real goal of achieving their dream socialist state or globalist world. It's not their "issues" of global warming or opposition to Trump that they care about. They use global warming to tighten their grip on our wallets and the anti-Trump thing to regain their grip on power.
But they also use both of them to achieve their socialist/globalist utopia.
I don't think any other candidate for president could have resisted and fought off this Leftist onslaught like Trump has. We are lucky to have him at a time when the viability of our country, as founded, is at stake.