The concept of net neutrality received what could be a serious blow on Thursday, as the U.S. House of Representatives rejected a Democrat-backed amendment that would have put net neutrality regulations into an upcoming telecom bill now being debated in Congress.

In a vote that fell mostly along party lines, the amendment was rejected 269-152, with 14 members not voting, and occurred after a day of debate. Republicans represented the large majority of votes to strike down the amendment, with most Democrats supporting the legislation.

"We are making progress, and although we did not prevail tonight, we intend to prevail in the end," he said in a statement. "Net Neutrality is as basic to the function of the Internet as non-discrimination is to the U.S. Constitution. We will win because we must."

If passed, the amendment would have been attached to the Communications Opportunity, Promotion, and Enhancement (COPE) Act, which was approved by a House committee in April. The telecommunications industry and Republicans say the bill has sufficient provisions to prevent the creation of a "two-tier Internet."

However, opponents disagree, saying the word of the telecoms that they would not charge for priority access is not enough. Telecoms maintain that it is their right as owners of the pipes to charge those who use excessive amounts of bandwidth.

Companies such as Google, Microsoft and Yahoo have come out in support of net neutrality, along with a coalition of musicians. Google CEO Eric Schmidt published an open letter on Thursday, calling for consumers to contact Congress and demand that the Internet remain a level playing field.

"The phone and cable monopolies, who control almost all Internet access, want the power to choose who gets access to high-speed lanes and whose content gets seen first and fastest," Schmidt wrote. "Creativity, innovation and a free and open marketplace are all at stake in this fight."