The congressional upper chamber also voted to extend a cut in taxes that fund Social Security, a federal program that provides income to retirees.

For most of the year, US lawmakers follow political, and often partisan, imperatives when conducting the nation’s business.

But in late December, a different imperative emerges: a desire to wrap up legislation so that lawmakers can get home ahead of the Christmas and New Year holidays. The end result is sudden and swift compromise, producing last-minute bills that get voted on with a minimum of debate, often before lawmakers even have a chance to fully read the legislation.

The Senate’s top Democrat, Majority Leader Harry Reid, spoke moments on December 17 before the chamber approved close to US$1 trillion to fund the federal government through the end of the current fiscal year - a bill more than a thousand pages long.

The federal funding bill was approved 67 to 32, one day after it passed the House of Representatives.

The Senate also approved a two-month extension of a payroll tax cut that boosts paychecks for 160 million Americans. Democrats had sought a full-year extension, to be paid for by a surtax on millionaires' income.