WEF figures indicate that the worldwide retirement savings gap in 2015 is estimated to be $70 trillion, with the largest shortfall being in the U.S.—and, just in the U.S., the savings gap is growing at a rate of $3 trillion per year.

A big part of the problem is the number of people who lack the opportunity to save in an employer-sponsored retirement plan. Indeed, MarketWatch cites estimates putting the number of people who do not have a retirement plan at work at about 50 percent of the workforce: some 55–63 million workers altogether.

Even though the Trump administration has killed off the safe harbor, some of the states that have already enacted retirement plans intend to proceed with them—at least for now. But if that action is halted by the government—and only seven states have already passed retirement plans—what’s to be done?

According to Anna Rappaport, president at Anna Rappaport Consulting and chair of the Society of Actuaries’ Committee on Post-Retirement Needs and Risks, people shouldn’t be looking to very small employers to add retirement plans.

In the report, Rappaport says, “There have been a variety of efforts to make it easy for small employers [to set up plans], but there remain many small employers who do not set up plans.” This is at least partly due to the expense and complexity of health care plans, which for employers are usually a priority. But that doesn’t mean there isn’t a solution.

Rappaport adds, “We need to think about where the coverage problem is coming from. Two big sources of the coverage problem are very small employers and people who do not have ongoing regular full-time jobs. I think it would make sense to do an honest assessment to see how much improvement in coverage is achievable.”

And that improvement could come, first and foremost, from improving Social Security benefits, especially for those at the low end of the income scale. “Social Security is extremely important and that must be recognized,” she says.

And after that? A federal auto-IRA that could be combined with the existing government myRA program, followed by the improvement of low-paying jobs and expansion of employment opportunities.

While there’s been some suggestion that multi-employer plans could provide an answer, Rappoport isn’t so sure. “I think it is important that adequate controls be in place, and that care should be taken how they are structured,” she is quoted saying, adding, “I doubt that they will increase coverage very much unless there is a mandate, and this also seems unlikely. I strongly prefer improving Social Security to mandating an additional layer of coverage.”