If you’re an ambitious Republican, it’s time to start thinking about challenging Donald Trump for the GOP presidential nomination in 2020. If you don’t get going now, you’re doomed to be too late. Unless you’re a celebrity with hundreds of millions of dollars at your disposal, you’ll need to lay the groundwork for your campaign very, very early. Raising the necessary funds will mean assembling the right team, and that will take a lot of wheedling.