Washington( CNN) Fiona Hill, the last witness in two weeks of televised impeachment hearings, constructed the example against her old boss President Donald Trump better than Democrat ever have.

And she also effectively warned that the Republican defense of the President — by peddling Ukraine conspiracy theories — was in danger, in itself, of becoming an extension of the 2016 Russian election scheme that is tearing American politics apart and draining public confidence in its democracy.

Hill — a British-born non-partisan Russia expert who also wrote a book on Vladimir Putin — was the star witness in a day of witnes that bring many of the threads of the Democratic example together and who left the Trump administration earlier this year. Using authoritative and clear language, Hill — who left the Trump administration earlier this year — spelled out her reactions to the pressure campaign unfold before her eyes. But Hill said she only really began to understand the scandal herself while watching evidence from Trump's ad hoc messenger to the new government in Kiev Gordon Sondland.

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