It began with a bill from a freshman Congressman with no political experience. The idea that sprung from the bill, that foreign-earned profits repatriated by U.S. firms could be used to fund infrastructure improvements, has taken on a mini-life of its own.

In May 2013, Rep. John K. Delaney (D-Md.) introduced legislation to create an infrastructure fund seeded by the sale of $50 billion in bonds with 50-year maturities. U.S. corporations would be encouraged to buy the bonds by repatriating, tax free, part of their foreign earnings for each dollar they invest. Based on a predetermined ratio, bidders for the bonds would be able to repatriate a certain amount of dollars for each dollar they invest in the fund. The fund, meanwhile, would leverage the $50 billion investment to provide many more billions of dollars in infrastructure loans or guarantees.

Despite garnering plaudits—former Transport Secretary James H Burnley, IV, a veteran of Washington's transportation battles, called it the most original financing idea he'd seen in 30 years—Delaney's bill languished in legislative limbo. Now, just in the past few days, the concept has caught fire. In his fiscal 2016 budget request, President Obama proposed a mandatory one-time 14-percent repatriation tax to pay for half of his six-year, $478 billion infrastructure funding proposal (the balance would come from motor fuel tax receipts). Last Thursday, Sens. Barbara Boxer (D-Calif.) and Rand Paul, (R-Ky.), introduced legislation to allow companies to voluntarily repatriate earnings at a rate of 6.5 percent, well below the current 35-percent U.S. corporate income tax rate, as long as the proceeds are transferred into the Highway Trust Fund, the mechanism that funds infrastructure projects. U.S. firms have parked about $2 trillion in foreign earnings overseas, largely because they are loath to pay a 35-percent tax upon the funds' return to the U.S.

The Paul-Boxer bill, called the "Invest in Transportation Act of 2015," would give companies up to five years to complete the transfer into the Trust Fund. The favorable tax rate would only apply to reparations that have exceeded each company's average reparation activity in recent years, according to the legislation. Funds to be transferred must have been earned in 2015 or earlier. No funds may be spent on executive compensation increases, stock buybacks, or shareholder dividends for three years following the program's end.

Delaney, who has reintroduced his own bill, lauded Sens. Boxer and Paul for putting the issue in a "bipartisan sweet spot" where a deal can get done. "Two years ago when we started on this framework, no one was talking about combining international tax reform and infrastructure," Delaney said. "I'm heartened that more and more legislators are advocating our approach."

Congress has less than four months to pass a bill reauthorizing the Trust Fund, which is up for renewal May 31. If Congress cannot pass legislation, it can extend trust fund authority for a period of time; the current law, which was signed by President Obama in July 2012, was set to expire in September 2014 but was extended through May.

C. Kenneth Orski, a long-time public policy consultant and expert on infrastructure issues, said he doesn't think the idea of connecting repatriation and infrastructure will succeed because it doesn't have sufficient support in the House. Orski said that if a bill does advance, lawmakers would have to decide to either make repatriation mandatory as outlined in the White House budget proposal or make it voluntary as in the Boxer-Paul bill. Supporters of the Administration's plan argue that a voluntary scheme may not yield the revenue needed to create a robust funding stream.

Boxer's support could be a key factor in moving the legislative needle. Boxer, who is chairman of the Senate Environment and Public Works Committee, was the driving force in Congressional passage—against long odds—of the 2012 highway funding legislation. Boxer's influence, combined with the notion that she may want to leave a legacy of legislative success in the transport arena before she retires when her term is up in 2016, could help the initiative gain traction in both the House and Senate.