Sen. John McCain on Thursday called for President Bush to fire the chairman of the Securities and Exchange Commission, while he and his campaign charged that Sen. Barack Obama is using the current economic crisis as a political opportunity.

McCain, distancing himself from the Bush administration, said heads should roll, starting with SEC Chairman Christopher Cox, appointed by the president in 2005.

"The primary regulator of Wall Street, the Securities and Exchange Commission (SEC) kept in place trading rules that let speculators and hedge funds turn our markets into a casino," he said. "The chairman of the SEC serves at the appointment of the president and has betrayed the public's trust. If I were president today, I would fire him."

McCain said the SEC allowed "naked short selling," which means that traders were selling stock without ever owning it. He also said federal regulators last year eliminated the "uptick rule" that regulates short selling and has protected investors for 70 years.

With Wall Street mired in meltdown mode, the Republican presidential nominee slammed the Democrat-controlled Congress for doing nothing and, pushing the unpopular president aside, demanded the administration take swift and severe action.

"We cannot wait any longer for more failures in our financial system," McCain said in Cedar Rapids, Iowa. "Today we need a plan that doesn't wait until the system fails."

Meanwhile, top aides to the Republican said Obama and his advisers are exploiting Wall Street's financial problems for political gain.

Aide Steve Schmidt, who worked for the Bush-Cheney team in 2004, told reporters Thursday aboard McCain's plane that Obama is "cheerleading this crisis."

The Arizona senator said Wall Street greed and corruption was to blame for the crisis. "There was no transparency into the books of Wall Street banks. Banks and brokers took on huge amounts of debt and they hid the riskiest investments. Mismanagement and greed became the operating standard while regulators were asleep at the switch," he said.

He called for the creation of a mortgage and financial institutions trust -- the MFI -- to "work with the private sector and regulators to identify institutions that are weak and take remedies to strengthen them before they become insolvent."

"This will get the Treasury and other financial regulatory authorities in a proactive position instead of reacting in a crisis mode to one situation after the other. The MFI will enhance investor and market confidence, benefit sound financial institutions, assist troubled institutions and protect our financial system, while minimizing taxpayer exposure," he said.

McCain raked his Democratic rival, saying he "didn't lift a hand to avert this crisis."

"Senator Obama has never made the kind tough reform we need today. His idea of reform is what his party leaders in Congress order him to do. We tried for bipartisan ethics reform and he walked away from it because his bosses didn't want real change," he said.

"Those same congressional leaders who give Senator Obama his marching orders are now saying that this mess isn't their fault and they aren't going to take any action on this crisis until after the election. Senator Obama's own advisers are saying that crisis will benefit him politically," McCain said. "My opponent sees an economic crisis as a political opportunity instead of a time to lead.