James Clapper, Director of National Intelligence from 2010 to 2017, says yes. From Facts and Fears, Hard Truths from a Life in Intelligence by James R. Clapper with Trey Brown published in 2018.
“…of course the Russian efforts effected the outcome. Surprising even themselves, they swung the election to a Trump win. To conclude otherwise stretches logic, common sense, and credulity to the breaking point. Less than eighty thousand votes in three key states swung the election. I have no doubt that more votes than that were influenced by this massive effort by the Russians.”
Trump must go