Sen. Tom Harkin's retirement plan proposal – released Jan. 30 — has some flaws, not the least of which is that employers who offer 401(k) plans would have to change their current plans to be more like defined benefit plans if they didn't want to be forced to adopt Harkin's USA Retirement Fund, according to the National Association of Plan Advisors.

Just offering any 401(k) is not enough to keep employers from having to provide a USA Retirement Fund account. Under the legislation, an employer-provided 401(k) must include automatic enrollment and a lifetime income option. If it does not, it must change its plan to do so.

"In order for employers to be exempt from the USA Retirement Fund requirement … they would have to alter their 401(k) plan to look more like a defined benefit plan, which may be a burden on the employer. Instead we should focus on expanding retirement savings opportunities rather than trying to change the current system," said Brian Graff, executive director and CEO of the American Society of Pension Professionals & Actuaries and NAPA.