This is the issue that Andrew Biggs implicitly raises in his Wall Street Journal column highlighting the jump in the size of the projections of the Social Security shortfall since 2008. Biggs complains that progressives have responded to the economic collapse by proposing an increase in benefits that would make the shortfall even larger rather than supporting plans for eliminating the projected shortfall. While Biggs' focus is explicitly the solvency of the program, the actions of progressives can only be understood against the larger economic context.
The calls for expansion of benefits are at least in part a response to the economic collapse.It's worth noting that this collapse was 100 percent preventable and that it was one of the worst blunders in the history of economic policy-making in the history of the world. Unfortunately the top economic advisers in both political parties whose errors were responsible did not have their standing affected by this mistake.
As a result of the collapse, many people nearing retirement saw much of their savings disappear as the stock market collapsed, house prices plummeted and they lost their jobs during their peak savings years. This meant that millions of workers had to draw down their savings to support their families at a point where they had planned to be accumulating wealth for retirement. In addition, due to the weakness of the labor market created by high unemployment, tens of millions of workers have seen stagnant wages over the last six years when they could have expected to see real wage growth in the neighborhood of 1.0 percent annually had the economy continued on the path projected in 2008.
In short, the collapse hugely increased the need for Social Security, which is the basis for the response of progressives. Biggs is correct that the cost of additional benefits will have to be covered at some point, but there is no obvious reason that it is necessary to come up with the full plan today. Part of the cost can be recovered by increasing the payroll cap as has been proposed by people across the political spectrum.
It is likely that we will need some increase in the payroll tax at some point, but there is little reason that the exact timing needs to be pinned down today. In the decade from 1980 to 1990 the payroll tax increased by over 2.0 percentage points. In spite of this hike, many conservatives tout the eighties as an economic golden age. It is difficult to see why it would be such a disaster if there were a comparable increase somewhere over the next three decades.
Workers care about their after-tax wages which are primarily determined by what they earn before taxes. Due to economic mismanagement and trade and regulatory policies that were designed to redistribute income upward, most workers have seen very little growth in before-tax wages over the last three decades. If they get an even share of the projected growth in compensation over the next three decades, then before tax compensation will be almost 60 percent higher in 2044 than it is today. It is understandable that progressives would be more focused on ensuring that workers get their fair share of economic growth than the risk 3-4 percent of these gains might be taken back in tax increases to support their retirement.