Rep. Adam Schiff of California on Sunday said Democrats will be keeping a close eye on acting Attorney General Matthew Whitaker, deeming him a “flawed appointment” who cannot be trusted to guide the Russia investigation. Mr. Schiff, who is poised to become chairman of the House Intelligence Committee, said his panel will root out and expose any efforts Mr. Whitaker takes to curb special counsel Robert Mueller’s probe into potential interference in the 2016 election. The acting attorney general has criticized the scope of the investigation in the past. Mr. Schiff also said Mr. Trump’s decision to tap Mr. Whitaker...