Here's the problem with ultimatums: If the group you're trying to influence refuses to budge, you have no choice but to use the leverage you've threatened to apply. So it looks as though Horry County Councilmen Howard Barnard and John Boyd will be going to Columbia next week to vent their unhappiness with the S.C. Department of Transportation.

The gentlemen, along with the rest of County Council, want the DOT to consider routing the long-awaited Interstate 73 through southern Horry County. Never mind that the DOT dropped that part of the county from I-73 route considerations about a year ago, citing objections from federal agencies and environmental concerns as the reasons.

It apparently didn't register with Boyd that the interstate most likely would touch some part of his sprawling western Horry County Council district. Nor did it register with Barnard that this I-73 routing choice would not give South Strand residents their long-craved storm-evacuation route.

They and the rest of the council only woke up to the implications of that 2004 decision this year, after the agency further narrowed its considerations to routes that would link up with S.C. 22 hear Aynor. Boyd, having gotten an earful on this decision from unhappy constituents, exhorted the council to fight this decision. Council members responded this month with a resolution beseeching the DOT to resume consideration of a route through southern Horry County. It passed unanimously.

No matter. The DOT last week rejected the council's resolution, effectively quashing members' belated show of interest in the I-73 project. Instead, the agency will concentrate on refining the western Horry County route to minimize disruption of family farms and rural communities.

Barnard and Boyd, however, served notice on the agency that highway planners have until the end of next week to reopen consideration of a southern Horry County route.

If the agency fails to comply, the two said they would denounce it at a news conference from the steps of the S.C. Capitol in Columbia. The event promises to be a spectacle that further confirms inland suspicions that Horry County folks march to a drummer whose cadence is inaudible in the rest of South Carolina.

As DOT officials have pointed out, changing course on I-73 now would set planning back for years, limiting or eliminating federal financial support for the project.

But as Barnard's letter on today's editorial page makes clear, this message is not getting through.

Don't misunderstand: The South Strand needs and deserves better highways. But I-73 was never the right candidate to fulfill the area's road needs because federal funding, if it comes, will be tight.

The project must be built for the lowest cost possible, which is why tying it to already-built S.C. 22 is so attractive.

The solution for the South Strand lies in the county's proposed Road Improvement Development Effort II plan, which includes extending Carolina Bays Parkway from S.C. 544 to S.C. 707 near Holmestown Road.

As the parkway likely will become part of Interstate 74, that extension would provide residents from the Georgetown County line to Surfside Beach the first-class evacuation route they crave. Rather than tilt at windmills in Columbia, the better bet for Barnard and other council members would be to come up with a realistic plan for financing RIDE II, and let the DOT get on with building I-73.