Congressional jockeying over the fate of the Export-Import Bank is picking up, with four months left before the bank's charter expires.

House Democrats on Thursday celebrated that the bank appeared to have gained enough support for a long-term reauthorization, with more than 160 members supporting a Democratic seven-year measure and 58 Republicans signed on to a five-year extension.

In the Senate, Joe Manchin, D-W.Va., and Mark Kirk, R-Ill., also are planning to introduce a bill in the upper chamber to reauthorize the bank.

Despite their apparent majority in Congress, Ex-Im supporters face entrenched opposition from conservative Republicans who view the bank as cronyism and an enabler of corporate welfare. Ex-Im is the official export credit agency of the U.S., helping businesses sell in foreign markets with loans, credit guarantees and other financing aid.

The bank’s opponents, although outnumbered, have one major advantage: All they have to do is run the clock out to see the bank’s charter expire June 30.

Congress’ top critic of Ex-Im, House Financial Services Committee Chairman Jeb Hensarling, is set to underline his opposition to reauthorizing the bank in a speech scheduled for Friday at the Conservative Political Action Conference just south of Washington.

“There is probably no better poster child of the Washington insider economy and corporate welfare than the Export-Import Bank. Its demise would be a resounding victory for the Main Street competitive economy,” Hensarling said in a preview of the speech sent out by his office.

“I believe it is a defining issue for our party and our movement,” Hensarling added.

Hensarling and other conservatives view ending the bank, which benefits some large companies such as Boeing, as a chance to demonstrate that conservatives can stand up to special interests.

But the bank’s supporters were able to demonstrate broad support this week, flying in nearly 700 people from businesses around the country to prevail on Congress.

“There is no plan B for a lot of these companies. A lot of companies I talk to, there is no backup plan” for maintaining export business without Ex-Im, said Lauren Airey, a representative of the National Association of Manufacturers, which organized the fly-in.

Other groups representing businesses that rely on Ex-Im financing will continue similar fly-ins in the weeks ahead to put pressure on lawmakers, Airey said.

The last reauthorization of Ex-Im, before the short-term extension won as part of a broader budget deal in September, passed the House with 330 votes in 2012.

Ex-Im’s critics, however, feel good about their positioning.

“I think we’re in a really good position to end a federal program. It’s not very often you can say that,” said Dan Holler, who represents the conservative group Heritage Action. “They literally have to do nothing to score a major victory,” Holler said of conservatives.

Heritage Action countered the business groups this week by handing out flyers shaped like airline boarding passes including state-specific information highlighting the relatively small share of total commerce supported by Ex-Im.

Holler downplayed the possibility that Ex-Im would be reauthorized in a deal like the one that extended its life in September, with reauthorization attached to a bigger must-pass bill.

Citing the fact that Hensarling, House Ways and Means Committee Chairman Paul Ryan and House Majority Leader Kevin McCarthy all have indicated opposition to the bank, Holler said: “I think we’re in a pretty good position.”