The legislative package proposed by Joe Biden on Tuesday is, to steal the president’s own words from a bygone political era, a “big fucking deal.” His proposed bill comes with an eye-popping price tag of $3.5 trillion in new government spending. Its principal provisions would establish universal pre-kindergarten and paid family leave, enact a clean energy standard and invest in renewable energy, and build on the infrastructure provisions of a separate, smaller bipartisan proposal.

If the bill passes, it will be the largest expansion of the American welfare state since Lyndon Johnson’s Great Society, which established Medicare and Medicaid, along with a host of other welfare programs, in the mid-1960s. It would also represent significant—and long overdue—progress on climate change, with Democrats asserting that under the bill’s provisions the United States would reach 80%-clean electricity by 2030.

How the bill will pass, however, is the question. Democrats intend to use a complicated legislative mechanism called “budget reconciliation.” This would allow the bill to pass through the Senate without being subject to a Republican filibuster—a rule that effectively raises the threshold of to pass from fifty to sixty votes. Reconciliation, though, can only be used so long as the legislation only contains budget provisions. This is the mechanism that Democrats used to pass Mr. Biden’s COVID-19 stimulus bill and how Republicans passed former President Donald Trump’s Tax Cuts and Jobs Act in 2017.

Passing the bill with their bare majority of 50 seats plus Vice President Kamala Harris’ tie-breaking vote in the Senate will be difficult, but possible. Moderate Democratic holdouts like West Virginia Senator Joe Manchin and Arizona Senator Kyrsten Sinema have signaled possible support for Mr. Biden’s legislation. There will surely be negotiations over the reconciliation bill, and the total spending may be cut down over the next few weeks. Odds are good, however, that Congress will soon pass a bill that looks something like Mr. Biden’s $3.5 trillion proposal.

But the bill’s path to passage through reconciliation is revealing of how warped the legislative process in Washington, D.C. has become. The Great Society, like Franklin Delano Roosevelt’s New Deal before it, was a reform package composed of a series of bills, each deliberated over and voted on separately. This is because the parties had not yet weaponized the filibuster to empower a relatively small minority of legislators to stall any bill indefinitely. Today, the Senate can only pass one major bill every fiscal year with reconciliation. With a small number of opportunities to take advantage of the process, everything has to be incorporated into one, massive piece of legislation.

If Mr. Biden’s reform package was broken up into separate pieces of legislation, legislators could take issue with specific provisions, engaging in the horse-trading and pork-barrel dealing that is, for better or worse, part and parcel of politics in the United States. Under the current circumstance, however, any issue that any legislator takes with any provision puts the entire piece of legislation in jeopardy. Further, Democrats will be unable to include any item not ruled as “budgetary” in the package, which means, for example, that certain key climate regulations could be struck from the bill by the Senate’s Parliamentarian, the appointed official who rules on such matters.

Whatever one thinks of Mr. Biden’s proposal, it’s clear that this is no way to do legislative politics. It's not that his proposal is bad, or wanting because it doesn't command bipartisan support in Congress—it's just that it could be better, were the filibuster not holding the legislative process hostage. In a healthy American democracy, provisions could be broken into smaller pieces of legislation, including non-budgetary items, and examined one-by-one. Instead, Congress is forced to draft ridiculous omnibus bills to exploit arcane loopholes to get just about anything done. Today, it’s a foregone conclusion that Republicans will filibuster anything else, just as it was a foregone conclusion that Democrats would filibuster any of Mr. Trump’s legislative priorities. Unless the filibuster is significantly reformed, the legislative process in the United States Congress will remain a messy sham.