U.S. stock futures are slightly down as investors await the results of a key Eurozone vote and Alcoa’s (NYSE:AA) earnings report.

Futures on the S&P 500 Index are down 0.61 percent at 8:30 a.m. ET, futures on the Dow Jones Industrial Average are down 0.43 percent, and futures on the Nasdaq 100 are down 0.30 percent.

After Monday’s euphoric rally on France and Germany’s promise to unveil a Eurozone bailout plan by month’s end, market sentiment on Tuesday is subdued as investors await a key vote from Slovakia on the expansion of Eurozone bailout fund EFSF.

Slovakia is the only Eurozone member that still has not approved the expansion, which requires the affirmative vote of all Eurozone members.

A key argument from Slovak politicians against ratifying the expansion is that Slovakia, a relatively poor European country, should not be burdened by the profligacies of richer Eurozone members like Greece.

Slovak Prime Minister Iveta Radicova, however, has vowed to push through the approval for EFSF expansion.

Investors are also waiting for Alcoa’s earnings report, which will be released after the closing of Tuesday’s session.

Alcoa earnings are important because the aluminum company is seen as a bellwether for the global economy and unofficially kicks off each U.S. earnings season.