Popular government programs like Social Security and Medicare are called the third rail of American politics for good reason. Unilateral efforts to cut or devolve them generate significant public backlash—indeed, the most effective, early political attack on the Affordable Care Act was based on its provisions that cut Medicare spending. But our sense of these issues’ political explosiveness is shaped in a huge way by the fact that conservatives have never accepted the social compacts of the New Deal and Great Society, and have tried to undermine them aggressively for decades.

The canonical example of third rail politics is the GOP’s doomed 2005 push to privatize Social Security. After a reelection campaign of jingoism and fear mongering, George W. Bush claimed he’d won political capital and set about spending it on an unrelated plan that would’ve diverted significant payroll tax revenue into private investment accounts. Had he succeeded, many retirees would have become vulnerable to the vicissitudes of the market, and the guaranteed-benefit pension aspect of Social Security likely would have disappeared.

Liberals take great solace in the fact that Bush failed, and will reprise their strategy of unwavering opposition and refusing to negotiate when Republicans introduce plans next year to repeal the Affordable Care Act and phase out Medicare. Their resistance may well succeed.

But before they embark upon it, they should consider the possibility that, like everything in the Trump era, things probably won’t go precisely according to plan. Past GOP attacks on entitlement programs have been fairly frontal. Trump and his agenda-setters on Capitol Hill are going to do their best to keep this one off of the front pages.

In the end, Bush’s Social Security privatization never got a vote in Congress. In the face of intense public and Democratic Party objections, Republicans shelved it and then tried to pretend it never happened. But that was not for lack of effort on the part of privatizers, including Bush himself, who barnstormed the country trying to secure popular support for the plan.