Sunday on ‘This Week’: Newt Gingrich, Rep. Adam Schiff, and Douglas Lute Gingrich, Schiff, and Lute will appear on "This Week" Sunday.

 -- After President Trump tweeted he was under investigation in the expanding inquiry into Russia’s interference in the 2016 election, former House Speaker Newt Gingrich, author of the new book, "Understanding Trump," and House Intelligence Committee ranking member Rep. Adam Schiff, D-Calif., come exclusively to “This Week” Sunday.

Plus, former U.S. Ambassador to NATO Douglas Lute discusses foreign policy challenges confronting the Trump administration.

And the Powerhouse Roundtable discusses the week in politics, with ABC News Political Director Rick Klein, ABC News contributor and Republican strategist and pollster Kristen Soltis Anderson, Democratic pollster and PSB Research Executive Vice President Margie Omero, and CNN political commentator Marc Lamont Hill, author of “NOBODY: Casualties of America's War on the Vulnerable, From Ferguson to Flint and Beyond.”

See the whole political picture, Sunday on “This Week.”

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