(CNN) -- Sen. John McCain said Wednesday that if the financial rescue bill fails in Congress again, "the present crisis will turn into a disaster," and Sen. Barack Obama told lawmakers it's time to "step up to the plate."

Both presidential candidates stressed bipartisanship as they called for Congress to act before heading to Washington to vote on the $700 billion financial rescue plan.

"We are square in the greatest financial crisis of our lifetimes. And I am pleased to report that today, I will be returning to the floor of the Senate to vote on a bill that marks a decisive step in the right direction," McCain said at a campaign event in Kansas City, Missouri.

"Today, with the unity that this crisis demands, Congress will once again work to restore confidence and stability to the American economy," McCain said.  Watch what McCain says about the bailout Â»

The Arizona senator and Republican nominee said there will be time later to assign blame for the situation, "but our duty right now is to fix the problem."

Obama also warned that the crisis could turn into a "catastrophe" without swift action from Congress.

The Illinois senator and Democratic nominee said he has been reaching out to leaders of both parties to help pass the plan. See bailout tracker Â»

"To the Democrats and Republicans who have opposed this plan, I say this: Step up to the plate and do what's right for the country, even if it's not popular, because the time to act is now," he said in La Crosse, Wisconsin.  Watch Obama speak out about the bailout Â»

As part of his lobbying efforts, Obama has called members of the Congressional Black Caucus to support the bailout. When the bailout came up for a vote on Monday, caucus members split 21 against and 18 for the bill, CBC spokeswoman Keiana Barrett said.

Obama campaign Co-chairman Rep. Jesse Jackson Jr., D-Illinois, was one of the CBC members who voted against the bailout but said he would consider switching  if more protections for homeowners are added to the bill.

Republicans accused Obama of failing to show leadership as the economic crisis unfolded. McCain said last week that he was suspending his campaign to focus on the situation.

Democrats accused him of slowing down negotiations, while Republicans said he helped sway some reluctant lawmakers.

Although McCain did not mention Obama by name Wednesday, he made what could be seen as a swipe as his opponent.

"This is a moment of great testing. At such moments, there are those on both sides of this debate who will act on principle. Of course, there are always some who think first of their own interests, who calculate their own advantage instead of rushing to the aid of their country," McCain said.

Meanwhile, Obama blamed the current crisis on greed and irresponsibility in Washington and on Wall Street.

"Let me be perfectly clear. The fact that we are in this mess is an outrage. It's an outrage because we did not get here by accident. This was not a normal part of the business cycle. This was not the actions of a few bad apples," he said.

After their campaign events, McCain and Obama were both returning to Washington to vote on the bailout package. Obama's running mate, Sen. Joe Biden, was also expected to vote on it.

The bailout proposal failed in the U.S. House on Monday. The version going to the Senate adds provisions, including raising the Federal Deposit Insurance Corp. cap to $250,000 from $100,000 per account, and will be attached to an existing revenue bill that the House also rejected Monday, according to several Democratic leadership aides.

McCain and Obama both support raising the FDIC insurance limit as a way of reviving talks on Capitol Hill.

The Senate vote is scheduled for after sundown, in observance of the Jewish holiday of Rosh Hashanah.

After pointing fingers Monday, Obama and McCain have both tried to strike a more bipartisan tone as they work on selling the financial
Where are Obama, McCain and Biden heading to? Who is returning to Washington? What did Obama ask the Congressional Black Caucus to do? Obama asks who to vote for bailout? What did Obama ask? Who calls on Congress to act? What is Congress asked to do?
Washington John McCain support the bailout. Congressional Black Caucus Congressional Black Caucus to support Both presidential candidates vote on the $700 billion financial rescue plan.
question: Where are Obama, McCain and Biden heading to?, answer: Washington | question: Who is returning to Washington?, answer: John McCain | question: What did Obama ask the Congressional Black Caucus to do?, answer: support the bailout. | question: Obama asks who to vote for bailout?, answer: Congressional Black Caucus | question: What did Obama ask?, answer: Congressional Black Caucus to support | question: Who calls on Congress to act?, answer: Both presidential candidates | question: What is Congress asked to do?, answer: vote on the $700 billion financial rescue plan.