With hindsight, it’s clear that the trigger wasn’t truly painful. Frankly, this should have been obvious all along. Under the trigger, the committee’s failure to agree mandates $1.2 trillion of deficit reductions over a decade. These occur through across-the-board cuts divided equally between defense and domestic “discretionary” spending — a catchall that includes housing, education, homeland security, law enforcement and much more. Facing this brutal prospect, the theory went, the committee would negotiate something more sensible.

But it wasn’t so brutal for three reasons. First, the cuts don’t take place until 2013; the public won’t worry about what might happen a year from now. Second, no one can know in advance precisely how the Pentagon and all those domestic agencies would actually allocate their cuts to specific programs and projects. People can’t object to cuts that aren’t identified. Finally, Congress can always undo the damage by repealing the trigger.

What would a genuinely brutal trigger look like? Here’s my proposal. Half of the required deficit reductions would come in across-the-board cuts in monthly Social Security payments for all recipients, including the poorest and neediest. The other half would occur through increases in everyone’s income tax rates. And all these changes would start in early 2012. Social Security checks would go down; withholding rates would go up.

Now, this trigger would have concentrated the attention of the supercommittee and everyone in the White House and Congress. Democrats could no longer claim that failing to put all spending — including sacrosanct entitlements — on the table would protect Social Security beneficiaries. Republicans could not argue that their opposition to tax increases would prevent taxes from going up.

Both Republicans and Democrats would recognize that failure to agree would subject them to a torrent of popular anger and abuse, because these automatic deficit reductions would be completely and instantly understandable by all Americans. People have no trouble telling when their take-home pay declines and their benefit checks shrink. And these abrupt changes would threaten the fragile economic recovery. That would be another source of popular backlash.

Given these grim consequences, I have little doubt that this trigger would have forced the supercommittee to reach agreement. The trigger wouldn’t have been pulled, because the fallout would have been too terrifying. Indeed, the adverse reaction would have been so great that, I suspect, even President Obama — who stayed conveniently aloof from the bargaining — would have involved himself.

The defects of the actual trigger seem so clear that I think it was probably intended to fail. Obama has now threatened to veto any congressional measure that repeals the trigger and the subsequent sequester, but this compounds the damage because the sequester is also bad policy. Leon Panetta, Obama’s secretary of defense, has already said that cuts to the Pentagon would severely weaken America’s military. The across-the-board reductions to domestic discretionary spending impose too large a burden on a small part of the budget (only 18 percent in 2010) and make no distinction between worthy and unworthy programs.

It would be encouraging if the president and Congress created a new trigger along the lines I’ve suggested and made the supercommittee resume negotiations, with a Dec. 24 deadline. Of course, this won’t happen, because Democrats and Republicans do agree on one thing: They don’t want to tackle the deficits; it’s too hard.