So far, it's extortion....a federal crime.
Whoever, being an officer, or employee of the United States or any department or agency thereof, or representing himself to be or assuming to act as such, under color or pretense of office or employment commits or attempts an act of extortion, shall be fined under this title or imprisoned not more than three years, or both; but if the amount so extorted or demanded does not exceed $1,000, he shall be fined under this title or imprisoned not more than one year, or both.
(June 25, 1948, ch. 645, 62 Stat. 740; Oct. 31, 1951, ch. 655, § 24(b), 65 Stat. 720; Pub. L. 103322, title XXXIII, § 330016(1)(G), (K), Sept. 13, 1994, 108 Stat. 2147; Pub. L. 104294, title VI, § 606(a), Oct. 11, 1996, 110 Stat. 3511.)
https://www.law.cornell.edu/uscode/text/18/872
And this is just the tip of the iceberg. Whenever Ukraine comes up, you'll find Vladimir Putin. That's guaranteed. So at this point, I don't see how anyone of good conscience in congress (Rethugs excluded as they have no conscience or soul for that matter) can oppose impeachment. Many in the IC have had enough. So should every single Democrat in congress.