One of the most significant findings of Mueller's investigations was that the Trump campaign did indeed contact Russians during the 2016 election. Furthermore, they never reported anything about it to the FBI, or any other police. In fact, they tried to deny it, to the point of lying about it and obstructing legal investigations.
This was unquestionably illegal. Whether Trump and his staff understood it was illegal or not doesn't matter, they clearly tried to hide it from investigators.
That alone is enough to convince me he shouldn't be let off the hook. The tax evasion & financial fraud, such as lying to banks, investors, and creditors, etc. will only add fuel to the fire.
Shame on spineless GOP politicians, Fox news & their wanna-bes, and all the voters who fail to understand this.