William Taylor, the United States’ top diplomat in Ukraine, testified Tuesday that President Trump was holding back military aid for Ukraine unless the country agreed to investigate Democrats and a company linked to Joe Biden’s family, providing lawmakers with a detailed new account of the quid pro quo central to the impeachment probe.
In a lengthy opening statement to House investigators, Taylor described Trump’s demand that ‘‘everything’’ President Volodymyr Zelenskiy wanted, including vital aid to counter Russia, hinged on making a public vow that Ukraine would investigat