Whatever it is, I would think it best for him to just go ahead and reveal it rather than let it be used as leverage against him. He's the most impervious-to-scandal politician I've ever seen and I think he could weather almost anything they've got.
The Russians used to be skilled at setting men up with hookers, and considering Trump's self-image as a ladies' man, if a woman threw herself at him in Moscow he wouldn't think it's anything but his animal magnetism. If there are videos the evangelicals would likely have some second thoughts. And if there is proof that the Russians have some financial hold on him, maybe big loans that could be called or under the table payments for vague "services," that might be worse.
