"We believe a process that results in common sense baseline rules is critical to ensuring that the Internet remains a key engine of economic growth, innovation and global competitiveness," the executives wrote. "An open Internet fuels a competitive and efficient marketplace, where consumers make the ultimate choices about which products succeed and which fail. This allows businesses of all sizes, from the smallest start-up to larger corporations, to compete, yielding maximum economic growth and opportunity."

Powerful telephone and cable companies have traditionally opposed net neutrality, arguing that they should have the right to manage their own networks as they see fit. After all, they own "the pipes," they say. In particular, AT&T (T) has been a vocal opponent of the rules, especially Genachowski's plan to extend them to wireless markets.

The telecom and cable industries have unleashed their army of lobbyists to press their case on lawmakers. Likewise, pro-net neutrality advocates like Google (GOOG) have been making the rounds of Capitol Hill arguing for the new rules. The latest letter adds some more firepower to the net neutrality boosters. From their point of view, it couldn't come at a better time.

Last week, 72 members of the Blue Dog Caucus and the Congressional Black Caucus sent a letter to the FCC urging the commission to soften the open internet rules. In language echoing that of net neutrality opponents, the lawmakers asked the FCC to "carefully consider the full range of potential consequences that government action may have on network investment."

"We would urge you to avoid tentative conclusions which favor government regulation," the moderate Democrats wrote, adding, "we remain suspicious of conclusions based on slogans rather than substance and of policies that restrict and inhibit the very innovation and growth that we all seek to achieve."

In response, Gigi Sohn, founder of pro-net neutrality group Public Knowledge accused these lawmakers of "betraying" their constituents.

"It's a pity that 72 members of the Blue Dog Caucus and the Congressional Black Caucus are deserting one of the fundamental planks of President Obama's platform -- a free, open and nondiscriminatory Internet," Sohn said in a statement. "The people who those members of Congress represent are the most at risk from the closed, controlling Internet that the phone and cable companies want.

"In parroting the misinformation put forward by the big telecom companies, the Blue Bell Caucus only condemns their constituents to inferior service and limited opportunities to succeed in an Internet-based economy," Sohn added.

Thus, the battle lines have been drawn. In favor of the new FCC rules are the biggest internet companies, prominent academics such as Harvard's Larry Lessig and Columbi's Tim Wu, and Washington, D.C.-based consumer groups like Public Knowledge and Free Press. Against increased regulation are the telephone and cable companies, free-market conservatives, moderate Democrats and The Wall Street Journal editorial page.

On Thursday, FCC Chairman Genachowski is expected to win passage of his proposed rules along a party-line vote among the five commissioners, with at least three in favor. Following the vote, the commission will accept public comments for a period lasting as long as several months before formally instituting the new rules.

Meanwhile, Google and AT&T have been locked in an increasingly bizarre battle over net neutrality and FCC calling rules. In the latest twist, AT&T has accused the search giant of using its Google Voice web-calling application to block service to a convent of Benedictine nuns, among others. Google has argued that it blocks calls only to expensive phone-sex chat lines and conference-call numbers, and has pointed out that local carriers accuse AT&T of not paying its bills.

Expect the rhetoric to heat up ahead of Thursday's vote.

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