Donald Trump Jr. effectively confirmed that he will campaign against Rep. Justin Amash, the first Republican to advocate for impeaching President Trump, in a Thursday tweet, saying that he hears "Michigan is beautiful during primary season."
Why it matters: Trump Jr. is the Trump family member with the largest following among the Republican base — and a powerful social media presence. Amash responded to Trump Jr.'s threat by tweeting: "if it's what you say I love it especially later in the summer" — a reference to the email Trump Jr. sent in 2016 after being offered dirt on Hillary Clinton by the Russian government.
Go deeper: Trump seeking candidates to primary Republican Justin Amash