House Budget Committee Chairwoman Diane Black. Photo: Andrew Harrer/Bloomberg via Getty Images

The Senate is on the cusp of passing a bill that would cut Medicaid by nearly $800 billion — and thus cause 15 million poor people to lose their health insurance — for the sake of financing a large tax cut for the rich.

Once that’s finished, the House GOP hopes to send over the next item on their party’s agenda: a bill that slashes health insurance for low-income people so as to finance a large tax cut for the rich.

House Republicans have been preparing their 2018 budget, the legislation that will allow them to pass filibuster-proof tax reform in the Senate. Reaching a consensus on that budget has been challenging, owing to the inherent tension between the party’s fiscal conservatives and military-industrial-complex enthusiasts. But over the weekend, Republican leadership and the House Budget Committee Chairwoman Diane Black found a way to have their tax cuts and Pentagon pork — and their deficit reduction, too: Heap more pain on poor and working people.

Specifically, the proposal would cut $200 billion from the non-discretionary budget, according to Politico. The outlet offers few details on the nature of those cuts, but suggests that the chopping block would feature Medicaid, food stamps, agricultural subsidies, and Medicare — in defiance of Trump’s oft-touted promise to leave entitlement benefits enjoyed by the elderly untouched.

Not every member of Paul Ryan’s caucus is eager for another round of betraying their most vulnerable voters to please libertarian billionaires, defense contractors, and suburban social Darwinists. But its conservative flank — which just demonstrated its dominance in the fight over Trumpcare — is champing at the bit:

The mandatory program cuts have won strong support by conservative lawmakers who are eager to target entitlement programs that are off-limits in the normal appropriations process.

The idea has become so popular that several budget members say they’ll only vote for a fiscal blueprint that includes those big mandatory cuts, putting leadership in a tight spot.

The trouble for these conservatives is that you can’t increase defense spending and cut the deficit on the backs of the poor alone. The United States doesn’t actually spend all that much on feeding, housing, and healing the unfortunate.

As with military spending, agricultural subsidies have powerful defenders within the GOP. So Agriculture Committee Chairman Mike Conaway balked at Black’s blueprint. So, too, did Energy and Commerce Committee Chairman Greg Walden, and several other committee chairs who wished to exercise more discretion over cuts affecting their priorities.

The pushback was strong enough to derail the leadership’s plans to unveil its budget on Wednesday and pass it out of the House by Friday.

The GOP can scarcely afford any more delays. To pass another round of tax cuts without Democratic votes, Republicans will need a new reconciliation bill. And you can’t have a new reconciliation bill without a new budget.

The longer it takes Republicans to resolve their internecine conflicts over handouts to big agriculture, Pentagon priorities, Medicare maintenance, and deficit reduction, the less time the party will have to craft its tax package.

Which is to say: The fate of the GOP agenda once again rides on the House’s far-right faction not letting the perfect be the enemy of upward redistribution — and its more moderate members agreeing to take their medicine.

The Trumpcare fight suggests that there are few limits to the amount of harm such “moderates” are willing to do to non-affluent people, even those who vote Republican.

The conflict between the GOP’s insatiable appetite for tax cuts; its tea party faction’s desire for deficit reduction; and the war-hawk wing’s lust for new weaponry isn’t going away. Which means no matter how much the Republican Party takes from benefits for working people today, it will be looking to grab a bit more tomorrow.

The Senate’s health-care fight is a life-or-death battle for thousands of Americans. But the true stakes of the Trumpcare battle go beyond the bill’s direct, devastating effects. If Senate Republicans prove that they can pass Medicaid cuts this draconian and unpopular then there’s little doubt that the GOP will seek another round of welfare-state retrenchment, and then another.

Conversely, if three Senate Republicans demonstrate that they are willing to step on their party’s agenda to protect their most vulnerable constituents, the party’s conservative faction will find itself playing a weaker hand. Consensus will likely turn toward an embrace of financing tax cuts through deficit expansion, rather than draconian cuts to the social safety net.

The reaction to Monday’s CBO score suggests the better angels of Susan Collins’s nature might prevail. But progressives shouldn’t take anything for granted — if they don’t beat back the forces of reaction in this battle, then Koch & Co. will breach liberalism’s fortress, and pillage what remains of our Great Society.