“The courts have specifically upheld pardons granted in situations where no charges had been filed yet. That approach to early or “pre-emptive” pardons is certainly controversial and may spark legislative and public debate, but it is generally lawful as a matter of precedent.”
So Trump may be able to pardon himself while no charges have been filed. But I would expect extreme controversy in Trump trying to vindicate himself on the issues of Russian involvement in his campaign for president. I would expect a Republican controlled congress (both houses) would vindicate Trump of any wrong doing in a strictly partisan vote.
The real question is whether or not they get away with this without a public backlash in the 2018 and 2020 elections. That is where I have no confidence in the American public, as in 2016 there was the lowest voter turn out in 70 years. If that apathy toward voting continues Trump will have no accountability at all.