Actually, it’s not yet a 24/7 Senate, and this is not yet something. On a near party-line vote of 51/49, the upper chamber passed a $4 trillion budget resolution. The resolution does nothing substantive except open up a reconciliation vehicle for a tax reform package to come later.

Mitch McConnell managed to line up every Republican behind this except for one. Want to guess who it was? Three guesses, and the first two don’t count:

The Senate has passed a $4 trillion budget blueprint that is a major step forward for President Trump’s ambitious promises for “massive tax cuts and reform.”

The 51-49 vote sets the stage for debate later this year to dramatically overhaul the U.S. tax code, cutting rates for individuals and corporations while clearing away trillions of dollars’ worth of deductions and special-interest tax breaks.

The vote on the budget resolution was largely along party lines. Sen. Rand Paul, (R-Ky) was the lone Republican to vote against the budget. In a statement, White House spokeswoman Sarah Huckabee Sanders said Mr. Trump “applauds” the Senate for the approval.

Dr. No Jr aside, this is the biggest legislative win for McConnell since … the previous budget resolution that opened a reconciliation path for ObamaCare. How did that work out again?

Donald Trump took a more optimistic view of the development, and pledged that Paul would vote for the tax cuts:

Don’t be so sure of Paul’s support for the tax cuts, nor of the steadiness of a few others. Earlier this week, I outlined the risks at The Week:

However, it seems that both McConnell and Trump have come around on the conclusion that they need wins now, not later, and the biggest agenda item — tax reform and the budget — will take as much Republican unity as they can get. Trump’s economic agenda relies on significant changes to the tax code, hoping to boost the economy high enough in the short run to get more political room to maneuver ahead of the midterms. At the moment, they have built more support for those efforts than McConnell managed with the ObamaCare repeal. Both Susan Collins and Lisa Murkowski announced that they would likely support the combined effort under reconciliation as it is currently proposed, and Rand Paul has signaled that he’s a probable yes, too.

Those three sunk ObamaCare repeal more than once. Getting the senators from Maine and Alaska — and hopefully Kentucky — onboard gives McConnell some breathing room — but he still needs Corker, McCain, and Flake to stay within the caucus. That leaves McConnell and Trump perilously close to failure on yet another bill. Both will take heat from constituents if they can’t get Trump’s economic agenda off the launch pad.

For now, Trump’s economic agenda eclipses his disruptor agenda, which left Bannon and his project out in the cold on Monday … for now, anyway.

That’s six potential wrenches that could get thrown in the works on tax reform. Two of those six (McCain and Flake) are in constant feuds with Trump, and another two (Collins and Murkowski) have defined themselves as GOP dissenters in this session. And of course we have Paul, who seems to be prepared to vote no on everything, including this non-binding budget resolution whose only real function is to set up the tax vote that Trump thinks Paul will support.

Perhaps it will all work out fine, but optimism in the 115th Session of Congress is the triumph of hope over experience. I’ll believe it when I see it.