It was the ghost towns and gold rushes — the raw frontiers with sparse, renegade residents — that gave the West a reputation for being mythically wild and independent.

But now, as the Wasatch Front and four other "super regions" of the Intermountain West begin to come of age, it's time to set the "lone cowboy" ideal aside.

According to a newly released report from the Brookings Institute studying the growth and potential impact of the Wasatch Front, Phoenix, Denver, Las Vegas and Albuquerque "megapolitan" regions, the Intermountain West is America's new, new frontier. But it won't survive unless it pulls together — and gets some help from the federal government.

"We celebrate the Western 'can do' spirit, but these places can't do it alone," said Mark Muro, policy director of the Metropolitan Policy Program at the Brookings Institute. "They in themselves can't knit the whole Southwest together with state-of-the-art transportation linkages, freight corridors and major shipment routes. They can't stabilize immigration or set up a national carbon reduction framework and climate change response. We want Washington to do the things it can do and empower these places to solve problems."

With 2.3 million residents in 2007, the Wasatch Front is the third largest of the five Intermountain West megapolitan regions — as defined by Brookings as areas where two or more metropolitan areas are combined into a single economic, social and urban system. Put together, the five regions are the fastest-growing in the country, with the potential to change America's economic future.

But pervasive challenges threaten to defeat the West before it ever arrives, unless changes are made. The area needs a more complete transportation network with roads, high-speed trains and intercity rail, the report says. Better regional planning that is not as heavily car-dependent and integration of immigrants are needed. A unified conservation effort toward water and electricity — limited resources in the West — are a necessity, according to the report.

Failure of the government to help resolve these challenges could be catastrophic for the whole country, according to Brookings Institute nonresident senior fellow Robert Lang, who participated in the study.