Voters are likely to hear the same message from other Democratic senators seeking re-election this fall, including Louisiana's Mary Landrieu, who like Warner made the bank the focal point of a campaign event Monday.
It's the most unlikely of campaign issues. Even some lawmakers say they never heard of the Export-Import Bank before becoming members of Congress. But with Republicans needing a net gain of six seats to win control the Senate, matters even as arcane as the "Ex-Im" can't be ignored.
The Ex-Im Bank provides loans, loan guarantees and credit insurance to foreign buyers of U.S. products. Congress must renew its charter before October to keep it functioning, and questions about that future are splitting Republican lawmakers.
The U.S. Chamber of Commerce and most governors want to keep the bank, opposing several conservative groups — including Club for Growth and Heritage Action — that are influential in GOP primaries and anti-establishment Republican circles.
Caught between their conservative base and pragmatic business groups, some Republican candidates are tip-toeing around the issue. For Democrats in toss-up states such as Landrieu in Louisiana, it's a chance to label their GOP opponents as beholden to the ideological right at the expense of creating jobs.
Landrieu is highlighting the Ex-Im issue in her re-election fight against GOP Rep. Bill Cassidy. She said Monday the bank promotes trade, creates jobs and helps small businesses, and Congress must reauthorize it "as soon as possible."
Cassidy is responding cautiously, raising questions about the bank's value without explicitly opposing its reauthorization. "Very serious reforms are required," Cassidy said.
His caution likely comes from the bank's ability to stir tea party supporters and other activists who want a smaller, less intrusive government. Well-run companies can get by just fine without the Ex-Im, Rep. Jeb Hensarling, R-Texas, said recently. He accused the bank of "political spending, both ideological and crony-based."
GOP lawmakers took note when House Majority Leader Eric Cantor, R-Va., suffered a stunning primary loss to a tea party-backed professor who strongly criticized the Ex-Im. Cantor's successor on the GOP leadership team — Kevin McCarthy of California — promptly opposed the bank's reauthorization. House Speaker John Boehner, R-Ohio, a longtime supporter of the bank, moved to a neutral position.
Some of Cassidy's fellow GOP House members from Louisiana support the bank's continuation, and some oppose it, exposing him to criticism no matter which way he turns. Republican Senate candidates in Iowa and Michigan also are approaching the issue warily.
In Virginia, Warner, seeking a second term, told the port workers Monday the U.S. government wouldn't need to such a bank in a perfect world. But to pull back from providing loans would put U.S. companies at competitive disadvantage.
"We live in the real world, not the theoretical world," Warner said. "And when China, Brazil, France, Canada all use these tools to the advantage of their companies, and somehow America, which has been using this Export-Import Bank for decades, would suddenly say, 'All right, we're going to take away this support,' this would cost us thousands of American jobs. That makes absolutely no sense."
His Republican challenger, Ed Gillespie, says the bank's costs don't justify its benefits. "It's hard to stand up to the Chamber of Commerce (and) the National Association of Manufacturers," Gillespie said, but it's the right thing to do.