That something better, they argued, is a guaranteed retirement account, or GRA.

A GRA, which would be both mandatory for workers without a pension plan and not subject to emergency withdrawals, would require “a mandatory minimum of 1.5 percent” from both workers and employers.

In addition, it would be managed by an independent government agency, which would also oversee investments made with the pool of money.

No independent retirement account here; “[i]nstead, low-fee diversified retirement portfolios would be created by a board of professionals who would be fiduciaries appointed by the president and Congress and held accountable to investors,” the pair wrote.

Able to choose investments more like a defined benefit plan, by managers whose income would not depend on those investment choices, such a plan would also incorporate fee transparency and keep its funds separate from government coffers, since the accounts would be owned by the individuals contributing.

Ghilarducci has already advocated a drastic change in the current retirement system, back in 2008, when she proposed a similar plan and was immediately assailed by Tea Partiers who loathed the idea.

James has come down on Ghilarducci’s side because he’d like to see retirement plans more closely resemble traditional pensions’ investing strategies, such as those used by the institutional clients Blackstone caters to, and incorporate more private equity investments.

While private equity is a substantial part of the institutional and pension world, it’s largely unavailable in 401(k) plans, which he has said simply don’t provide sufficient return, and certainly not as much of a percentage as pension plans can get through alternative investments—something to which 401(k) owners have little access or exposure.

In an interview with CNBC last year, James said, “The trick is to have these accounts invested like pension plans, so the money compounds over decades at 7 to 8 percent, not at 3 to 4,” which is the typical return of a 401(k). He added, “If we don’t do something, we’re going to have tens of millions of poor people and poverty rates not seen since the Great Depression.”