No one can really say if a Roth is "likely" to be double taxed in the future, but every other form of tax advantaged account suffers the same political risks. Only a few years ago(during the last crisis) Senator Dianne Feinstein proposed 'nationalizing' 401k plans, to 'protect' retirees of course. It went nowhere this time, but that might not be the case next time. Yet, Roth's have near term advantages as well, particularly for the very young investor. Due mostly to the standard deduction for a single person, if a young adult (or teenager) were to have their Roth funded by their Mustachian grandparents instead of an inheritance a decade or two later, those funds would be tax free (for the young adult) on both ends.
Also, a Roth IRA can also function as a wonderful savings vehicle for a *true* emergency fund, since the contributions (but not the gains) can be withdrawn without penalty at any age, for any reason. Also, there are about a dozen exceptions to the 10% penalty on the gains; including college expenses, a first home down payment (or actually, the first home in over 3 years), excessive health care bills, disablement, a tax judgement (if you get behind with the IRS itself) and death. While that last one doesn't benefit you directly, it benefits your spouse, so if each of a couple have Roth IRA's in their name; they protect each other from some of the economic issues of a death of a spouse. So even with the political risk, a Roth IRA is a wonderful financial instrument. But since it's not in Congress's own interests (for future taxes) they cap the annual contributions. So get them while you are young, fund them as well as you can, and fund your childrens' new Roth's as soon as they have a paycheck.