You might never spot an air marshal on your flight, but it’s reassuring to know one might be there. In a few weeks, though, many of them are likely to get pink slips — along with food safety inspectors, border patrol agents and countless other government employees who play a crucial if hidden role in everyone’s lives.

These and many other cuts to important programs like child nutrition and low-income housing are part of a giant buzz saw known as the sequester, which will indiscriminately slash $100 billion in discretionary spending beginning in January and will continue for nine years.

The cuts, mandated by the 2011 budget agreement, would not affect entitlement programs like Social Security, and have not received the same attention as the tax increases that are also scheduled to take effect in January. They are the rarely discussed part of the so-called fiscal cliff, and negotiators have little time left to prevent their impact. But all signs suggest that Republicans remain unrelenting in their insistence on preserving the full amount of the cuts, and adding many billions more.

The slogan that Republicans have relentlessly repeated on every talk show, and that Speaker John Boehner invoked Thursday — Washington has a spending problem, not a revenue problem — may sound superficially appealing to weary taxpayers, but those who mouth it never bother to give details on what their budget-cutting demands really mean. It is not an abstraction, like their vague calls for “entitlement cuts.” None of these brave budget-cutters want to go on television and say, cut the F.B.I. Or cut the Border Patrol. Or cut the Centers for Disease Control and Prevention. But that’s exactly what they’re doing by insisting on slashing discretionary spending. Republicans are so afraid of this reality that they won’t even detail their demands for cuts to the White House in the fiscal-cliff talks, instead waiting for President Obama to go first so they won’t be stuck with the blame.