Let me try to answer this question for you!
1. You are assuming that you must pay taxes in the US? Are you sure? Have you checked that the ratification of that law proposed by the IRS has happened in your state? Many states never legally signed to that bill... In many states paying taxes is a voluntary action based on assumptions and copying cultural behaviour out of fear of the armed forces of the governments. But in reality these armed forces have no legal reason to persecute you for not paying their "taxes" (which we would call something else if it was obvious that the mafia is behind all of that) and if so that would be a reason to get asylum in other countries. So please make sure that you must pay taxes in your state and that the bill proposed by the IRS has been ratified legally and must be enforced by state judges!
2. Why do you think that you would have to pay taxes for something that has never been evaluated in the national currency? Why do you think you have to pay taxes for something that is completely unrelated to the existing system? Are you using any service offered by the nation that would justify paying taxes for that service?
3. Why do you assume that DASH has some sort of "price" and where do you derive that from if you never exchanged it for that currency???
I believe that DASH is an open source database that lets us exchange and collaborate in a way that has never existed before, it has nearly nothing in common with our traditional monetary system, it is not even considered money in many places on this planet!!! If it would be money, then the IRS would have to take that money!!!
Until the IRS asks you for a share of that profits in crypto you have every right to deny that you ever intented to exchange that crypto for their national curency, as they have nearly nothing in common!!!
But if you really exchanged that crypto for national currency, then the whole story changes!! Because now you are using their services!!! Now you are playing their game and you must apply their rules!!! (Remember to check if they are playing by the rules (U.S. laws being ratified by the local state))
All of this text is just my humble opinion OBVIOUSLY!!!! And I am a crazy guy!!! Do not trust my words!!! Go and investigate!!!