Dear President Trump, you have a problem.
There's a story circulating that you have some sort of a relationship with Putin and/or Russia that compromises your ability to function as president. If it's true, it's a very serious problem.
You are having to spend too much of your valuable time denying it. There is an easy solution, Mr. President. Appoint an independent investigator that has a totally free hand and access to all information, including your tax returns.
If there's nothing there, you will be vindicated and make your antagonists look silly. This is such a simple solution that if you don't do it, it makes you look guilty.