U.S. senators this week will be offered the chance to take one of the least-glamorous step any politician can: self-imposed fiscal discipline that will earn one day of praise and a whole year’s worth of hard choices. They should take it, and begin explaining to the public some of the major challenges that lie immediately ahead for the country.

The fiscal discipline comes in the form of a pay-as-you-go budget – known by its shorthand name “pay-go” – that is applied when Congress wants to spend more on programs or collect less in revenues through tax cuts. Pay-go requires that those decisions be offset. The House passed such a measure this winter, with Maine Reps. Michael Michaud and Tom Allen supporting the measure.

The Senate, where Olympia Snowe and Susan Collins have long championed pay-go, passed weak requirements in 2003. The pay-go rules applied only to entitlement spending increases or tax cuts not assumed in budget resolutions. As long as they are part of the resolution, tax cuts and entitlement increases of any size were acceptable.

That’s not good enough. Pay-go rules were adopted by Congress in 1990, and were among several events that led to a balanced budget by the end of the Clinton administration. The measure, however, was allowed to expire in 2002 – but not before Congress had passed $700 billion in mostly tax cuts and some spending increases, which violated pay-go rules.

Legislation enacted since 2001 has added about $2.3 trillion to the deficit, according to the Congressional Budget Office. Half of this total is due to tax cuts between 2001 and 2006. Another third was due to increases in defense and security spending. Ten percent was attributed to increases in entitlement spending and 6 percent was because of increases in other domestic spending. Add these to other challenges such as shielding the middle class from the alternative minimum tax and making adjustments to Social Security, and Congress must work to avoid spending the nation into a financial hole.

The beauty of pay-go rules on both spending and tax cuts is that it offends politicians who want to rescue or enlarge programs without saying how they would be paid for and those who chose to make the Bush tax cuts temporary to hide their true long-term costs. Pay-go demands an accounting, and the more broadly it applies, the more thorough the accounting will be.

The Senate Budget Committee last week approved a budget resolution that extends the tax cuts only if they are offset. Sens. Snowe and Collins now have the opportunity to make their longstanding position on pay-go part of the resolution process. They should continue their support, and help the nation fairly face the difficult budget choices that will follow.