https://www.realclearpolitics.com/articles/2020/01/31/boltons_security_clearance_in_jeopardy_in_wake_of_book_leaks__142285.html

In July 2018, three months or so after becoming President Trump's national security adviser, Bolton hired both Army Lt. Col. Alexander Vindman as a Ukraine policy specialist for the National Security Council and his identical twin brother, Army Lt. Col. Yevgeny Vindman, as deputy legal counsel in the NSC's "ethics" office.

Bolton is totally responsible for this pair of unusual hires. There is no explaining this strange duo of appointments as something that the bureaucracy simply slipped over on Bolton. That is not Bolton's way.

Anyone who has been involved in national security affairs in Republican administrations since 1981 knows that it is impossible that the Vindman brothers were given sensitive jobs in Bolton's NSC without Bolton having become assured of their usefulness and loyalty to Bolton and his agenda. Both the Ukraine policy and the "ethics attorney" slots are of vast personal priority to Bolton.