For the last four years Republicans have used their small power perch in the House of Representatives to prime members for the day when they’d control the whole government. During each of those years, House Republicans passed a budget calling for vast, contentious reforms to Medicare, Medicaid, and other support programs. Republicans proposed crushing domestic spending to pay for regressive tax cuts and higher military spending, and then went further by laying out specific structural reforms to popular government spending programs.

Today they control the Senate as well, which represents significant progress toward their goal of complete control over the government. But as Republicans inch toward that goal they’re also growing less committed to their ideas.

Senate Republicans will not include detailed plans to overhaul entitlement programs when they unveil their first budget in nearly a decade this week, according to GOP sources… The GOP budget would balance in 10 years, according to GOP lawmakers familiar with the document, but it will only propose savings to be achieved in Medicare and Medicaid, without spelling out specific reforms as Ryan and House Republicans did in recent budgets.

House Republicans can proceed as they have in years past and pass a controversial budget of their own, but based on this report, it looks like the Senate isn't inclined to reciprocate. The simplest explanation for the commitment gap is that the GOP has a vice grip on the House, but a much more tenuous grasp of the Senate. Leaving Medicare privatization out of the budget is a simple way to make life easier for embattled GOP incumbents in Wisconsin, Pennsylvania, New Hampshire, and elsewhere.

But that basic political calculation speaks to a much bigger structural impediment facing the kinds of policies conservative activists want to see. The farther and farther you zoom out from the gerrymandered districts most House Republicans represent, the more difficult it becomes to build political support for the House Republican budget. At the swing state level it’s very hard. At a national level it’s probably impossible.

Back in 2012, Republicans hoped to skip directly from controlling the House alone to controlling everything. If Mitt Romney and Paul Ryan had won, the party would’ve been well prepared to implement the kinds of policies Ryan had trained his foot soldiers in Congress to vote for. Instead, the slower process of expanding majorities has exposed basic weaknesses in their position.

In 2012, Grover Norquist could, with some authority, declare: “We are not auditioning for fearless leader. We don't need a president to tell us in what direction to go. We know what direction to go. We want the Ryan budget…. We just need a president to sign this stuff.”

That line of thinking doesn’t hold up anymore. Can Republican presidential candidates run on privatizing Medicare if Senate candidates down the ballot can’t be seen supporting those kinds of reforms? Could they successfully spring a big entitlement devolution on the public in 2017 if they don’t campaign on it aggressively in 2016? George W. Bush tried that in 2005 and it blew up in his face. There’s no reason to think it wouldn’t play out the same way again.