The U.S. Capitol dome on Jan. 28. (Oliver Contreras/For The Washington Post)

FEW AMERICANS are much interested in the minutiae of congressional bargaining, but plenty are dead set against another descent into the dysfunction of a government shutdown. As congressional negotiators struggle to break an 11th-hour impasse in talks over border security, once again threatening funding for parts of the government, they might keep in mind the stakes. The lives of hundreds of thousands of federal workers would again be upended in the event of another shutdown, following the record five-week closure that ended Jan. 25. Americans’ already meager respect for their government would diminish further. The image and prestige of the United States itself would be further battered as people around the world took in the spectacle of a nation incapable of fulfilling basic functions of governance.

Those basic functions rest largely on the scaffolding of a political system whose ability to forge essential compromises is impaired by tribalism, ideology and creeping demagoguery. It is against those ingredients for further gridlock, amplified by President Trump and his incendiary rhetoric on border security, that the congressional conferees are battling.

Having apparently made progress on what seemed the central problem of avoiding another shutdown or a presidential declaration of national emergency — by forging a deal on border barriers — the lawmakers ran aground over the scope of deportation arrests. Specifically, Democrats insisted on imposing a cap on bed capacity at detention centers, where prospective deportees are held; the White House has wanted to expand that capacity in its ardor for expelling undocumented immigrants.

The Democrats justified their stance as a means of limiting the administration’s ability to conduct deportation sweeps that target migrants who may have lived in this country for many years and committed a minor crime. Their position, which reprises the Obama administration’s priorities, is sensible policy: Why waste scarce resources on rounding up nonviolent migrants who are well integrated in American communities and, often, families? But it is also probably poor politics. Already it has prompted Mr. Trump, never beholden to facts, to accuse Democrats of wanting to set murderers free to prey on the innocent.

It’s unsurprising that these negotiations would hit stumbling blocks. It’s critical that the stumbling blocks be overcome. If the conferees can find middle ground on border security and barrier funding — it was reported they had settled on funding amounting to perhaps a third of what Mr. Trump had sought for his wall — they should certainly be able to find it on detention bed capacity. Monday evening they were reported to have reached a preliminary deal. If so, Congress should vote on it, whatever Mr. Trump says about it, and keep the government open.

Lawmakers are paid to resolve problems. Let them resolve this one and present a deal to the president.