Congress deserves a limited — very limited — tip of the hat for Friday’s decision to re-authorize federal highway programs and the fuel tax that funds them. Although the bills that passed after months of contentious wrangling got the job done, they came at the last minute and did nothing more than the bare minimum needed to keep the country’s transport system tottering along.

Without Friday’s legislation, the government’s authority to levy federal gas taxes and the authority to spend about $100 billion on highway programs for the next two years, would have expired. At stake were an estimated 2.8 million construction jobs and the nation’s highway system, not to mention hundreds of lawmakers’ re-election hopes, so it was not surprising that a fractured and aimless House and Senate pulled themselves together to make affirmative votes.

What lawmakers did not do was resolve the real problem: Gas tax revenues fall far short of paying for all the work on highways that is needed and the trust fund from which highway funds flow is expected to be almost tapped out in two years. So Friday’s vote just got the old klunker a few more miles down the road and delayed until after this fall’s election the challenge of figuring out how to pay for future transportation needs.

What Congress will need to do, soon, is determine whether gas taxes, which have been the same for nearly 20 years, must increase or spending must decrease. To have any hope of answering those questions, Congress will first have to develop a sound and coherent national energy policy to guide the way. Many of the decisions involved will be divisive and unpopular, two things that most lawmakers avoid at all costs. But as the run-up to November’s elections continues, the questions of energy and transportation may be among the most important that candidates should be asked to address.

Americans love the freedom to travel anywhere, anytime on wonderful roads. They are unwilling to pay much for the privilege. Soon those two desires will come into conflict, and the lawmakers and president elected in November will have to come up with the answers.