The bipartisan infrastructure bill continues to inch toward passage, but Senate Democrats are already lining up their push for something bigger.

In a letter to his caucus, Senate Majority Leader Chuck Schumer announced the introduction of a budget resolution containing instructions for how to pass a $3.5 trillion infrastructure bill through the process known as reconciliation, which would not require any Republican votes, The Hill reports. Democrats plan to pass the resolution once the bipartisan bill moves to the House of Representatives.

That bill, the Infrastructure Investment and Jobs Act, made incremental progress toward passage as all 50 senators who caucus with the Democrats and 18 Republicans voted to limit debate on the bill on Sunday, Bloomberg reports. A final vote could come as early as Monday night, though some elements of the bill remain unsettled.

Among the elements left open for further debate is a proposed amendment that would relax language in the bill intended to regulate the cryptocurrency industry, Bloomberg reports. As of Monday morning, it was unclear if a package of amendments, including the one addressing cryptocurrency, would be allowed to reach the Senate floor for a vote.

If and when the Infrastructure Investment and Jobs Act does pass the Senate, it would move to the House, where the length of time it would take to then move to President Joe Biden to be signed into law remains uncertain. Speaker of the House Nancy Pelosi so far has maintained that she won't advance the bipartisan bill until the Senate passes the $3.5 trillion version as well, Bloomberg reports.

The budget resolution that Schumer plans to introduce would task 12 Senate committees with hammering out details of the spending involved, with a deadline of Sept. 15 for the bill to then be officially introduced, The Hill reports.

In order for the budget reconciliation process to succeed, all 50 members of the Democratic caucus need to get on board, which will mean appeasing Sens. Kyrsten Sinema and Joe Manchin, The Hill reports. Both have expressed trepidation at the level of spending and debt the $3.5 trillion plan would entail.

While the bipartisan bill in its present form calls for $550B of new spending split between items such as roads and bridges ($110B), the electric grid ($73B), broadband internet ($65B) and public transit ($39B), the budget reconciliation plan could include universal prekindergarten for 3- and 4-year-old children, expansion of Medicare and investments in clean energy, The Hill reports.