“There is always a temptation — and this is especially true in Washington — to completely rewrite the system and specify every detail of it, but the fact is that although the 401(k) system is imperfect in many ways, it’s a vibrant, active system,” he said. A government-specified program, he added, wouldn’t have the same vibrancy and would be tough to pass against industry opposition.

Instead, policymakers can take smaller steps to improve the Individual Retirement Account/401(k) system, John said.

To discourage people from tapping their retirement savings, policymakers could make it easier for old 401(k) balances to be automatically transferred to a person’s new employer. This would reduce cash-outs when people change jobs, he said.

Policymakers could help people save more through a mechanism called automatic escalation, which would move up the proportion saved from a worker’s income by 1 percent a year, John said. “This is something that exists right now and we have a certain number of companies that are doing that. We don’t have enough,” he said.

John also would like people to receive monthly statements from their plans showing how much income they can expect to see at retirement, so they can plan better.

For now, though, 401(k)s remain “as good a place as any” to save, as long as investors don’t treat the plans as rainy day funds, he said. The success of 401(k)s depends on long-term investment. Those who make pre-retirement withdrawals get hit with big tax penalties, plus they lose whatever they would have earned in interest. “Keep saving, save throughout your career, and don’t touch the money,” John advised.