Is the justice system in the USA irremediably broken because Trump pardoned even war criminals, traitors of the country, etc?

Because, if the president is allowed to pardon and absolve guilt after the fact, there’s a million ways for a sitting president to grift that. For example, what if the president intentionally engages in getting billions of dollars in a campaign slush fund and then just pardoned all the people involved in this fund?

I mean Paul Manafort for “traitors of the country”, because he was a direct conduit to the Russians through Konstantin Kilimnik and Oleg Deripaska, and Evan Liberty as “war criminals”, because on 2007, in a shooting rampage in Baghdad, killed more than a dozen civilians.