To hear some of the most vocal objectors to a proposed new Interstate 5 bridge across the Columbia River, only residents of Portland and Vancouver, Wash., have an interest in the thing. That’s just not true.

Both sides of the argument had their say earlier this week in a public hearing in Salem on House Bill 2800, which would authorize Oregon to contribute $450 million toward the $3.5 billion project. Gov. John Kitzhaber supports the measure and testified at the hearing.

A new bridge is vital. The current bridge hasn’t changed much since it initially was completed in 1958, yet the populations of the two states have more than doubled since then. The old bridge just wasn’t designed to handle the load it has today, routinely leading to long traffic tie-ups.

That might be tolerable, if only Portland-Vancouver commuters used the bridge. But more than half the economies of both states rely heavily on transportation, much of which must cross the existing bridge. Effectively parking trucks in the midst of traffic jams not only costs businesses money, it also adds dramatically to pollution.

Moreover, that aging, too-small bridge is not built to current seismic safety standards. In a state that sits squarely on the earthquake-prone Ring of Fire, that’s no small matter. Even more critical: The Cascadia subduction zone, just off the Oregon-Washington coast, is ripe for a major earthquake, scientists say.

Planning for the new bridge has had its problems. The approved design was too low, at 95 feet above the river, and had to be raised to 116 feet, which added to the price tag. Clark County residents do not want to pay for light rail, something Oregon believes is critical, and so on.

In the end, however, Oregon’s direct contribution of $450 million is a bargain, and tolls — user fees by another name — are a reasonable way of spreading the payment burden to those who will benefit directly from the bridge.

Neither state should assume, however, that federal largess will last forever where the bridge is concerned. In an era of tightened budgets and huge deficits, Congress needs to know that cool-headed Oregonians recognize the value of, and want, a new bridge now.