Donald Trump was determined during his presidency to cozy up to Vladimir Putin despite Russia’s interference in US democracy and objections by advisers, a former top aide claims in a new book, according to an excerpt published Saturday.

The new behind-the-scenes details from H.R. McMaster, Trump’s second national security adviser, come as Americans are set to decide whether the former president should return to the White House and as US officials warn of fresh foreign election meddling.

“After over a year in this job, I cannot understand Putin’s hold on Trump,” McMaster, in an excerpt from his memoir published in the Wall Street Journal, says he told his wife in March 2018.

A former lieutenant-general, McMaster became Trump’s national security adviser in February 2017, and says that from the beginning, discussions of Vladimir Putin and Russia “were difficult to have with the president.”

He says Trump connected “all topics involving Russia” to the federal investigation into Moscow’s interference in the 2016 election and possible ties with Trump’s campaign, a probe which would dog his entire presidency.