President Obama is going on a campaign this week, pushing Congress to spend on national infrastructure — the roads, rails and bike paths that Americans use every day. My colleague Greg Sargent speculates that, “The looming battle over infrastructure — particularly in the short term, over the fate of the Highway Trust Fund — could provide a particularly stark example of GOP anti-government sentiment colliding with reality.”

That might be so. But Obama hasn’t been realistic with the public, either. As in so many areas of policy, pointing out that the president’s position on infrastructure is better than most Republicans’ does not mean that his stance is great, and he doesn’t deserve the political points he is expecting.

Yes, Obama is right about one thing: There are good reasons to divert money into transportation, starting with the fact that the Highway Trust Fund is running dangerously low on cash, threatening building projects in the height of construction season. As part of its infrastructure campaign this week, the White House produced a report rehearsing the reasons to think that infrastructure spending — making it easier for people and goods to get from point A to point B — helps the economy.

The president is right about another thing: Congress should approve long-term infrastructure funding, enabling transportation officials to plan and finance big, multi-year projects and giving contractors confidence that funding will come through years down the road. The perpetual transportation funding crises the country has gone through can only discourage competitive bidding for government contracts.

For both of these reasons, Obama has proposed devoting $302 billion to transportation over four years, while Congress seems unable to plan more than several months ahead.

But the biggest problem in transportation policy is that the fair, efficient, self-sustaining system that worked for decades is now broken, and politicians have been too cowardly to fix it. Count Obama among them. The gasoline tax used to fill the coffers of the Highway Trust Fund. That made sense: Those who use the roads should pay for them. But lawmakers haven’t raised the gas tax since 1993, and the president isn’t asking them to. Instead, he has proposed taking a one-time windfall from a hypothetical corporate tax reform and driving it into infrastructure. Then what? After four years, the country would have to scrounge around for transportation money again. Obama isn’t proposing to fix the system. He’s proposing to buy the country a few good years and leave it to the next president to figure out how to shore up the system again.

Sen. Bob Corker (R-Tenn.) and Sen. Chris Murphy (D-Conn.) proposed a simple gas-tax increase last month, and they would like to see the tax level indexed to keep up with inflation. Rep. Earl Blumenauer (D-Ore.) last year proposed his own gas tax hike and indexing proposal. The administration hasn’t opposed these plans. It hasn’t said much good about them, either. Yet if anyone should be lecturing Congress on transportation infrastructure — if anyone deserves points for taking the right stand on the issue — it’s these guys.