Less than three months after passing a $900 billion coronavirus relief package, Congress is set to pass another massive relief package, the first legislative item on President Biden’s agenda. But unlike each of the previous coronavirus stimulus bills, this bill appears set to pass without a single Republican vote via a process known as “budget reconciliation.”

The reconciliation process has been used roughly two dozen times to pass legislation since 1980, but its use has become increasingly partisan in recent years following straight party-line votes on the Affordable Care Act in 2010 and on President Donald Trump’s tax cut legislation in 2017.

The Fix drew upon hours of footage and interviews with Washington Post reporters to analyze how Biden’s calls for unity could clash with his reliance on “budget reconciliation” amid a pandemic, an economic recession and the slimmest congressional majority in decades.