But regardless of their merits, they face the barriers of timing and cost, according to Marc Gerson, former majority tax counsel to the House Ways & Means Committee and a partner in Washington-based Miller & Chevalier.

"Congress is coming back for a short time before the elections," he noted. "For any proposal there is a short window of time so that's its unlikely we could see something enacted in the work period before elections."

The other barrier - the elephant in the room - is the cost of the proposals. "The statutory language will not be that difficult to draft, but the question is how much detail has the Administration given to Congress on the revenue offsets to finance those proposals," said Gerson.

"There will be a lot of debate and consideration as to what the revenue offsets would be. Expensing and the R&D credit are items that will generate some bipartisan support, but both the timing and revenue offsets are concerns that will affect the legislative process."

Gerson pointed to the administration's budget proposals as a possible source for the offsets.

"The February budget includes measures on international taxation, and oil and gas as well as other possible "pay-fors," he said. "Those might be likely sources to fund the these."

The offsets might bring a double-edged sword to the proposals, according to Gerson. "Companies could benefit, but the question is at what cost, and where they would end up on a net basis," he said. "For example, a high technology company may see a certain benefit from the proposals but at the same time it might be concerned with offsets aimed at U.S. multinationals, so on a net basis it might not be interested."

"The revenue offsets will be permanent and could change fundamental ways in which companies' international operations are taxed. The fact that the offsets are not spelled out in the proposal and that a significant amount of revenue is involved causes me to be concerned."

The legislation will likely be proposed in separate pieces so it will be possible to enact one or two rather than all three, Gerson suggested. The immediate expensing provision, at a cost of $30 billion, might be easier to enact than the permanent expansion of the R&D credit at $100 billion. But even if the legislation is proposed separately, there is a very tight legislative window."

Moreover, the pending midterms and change in the makeup of congress will have an impact, he said. "Both the expensing and the R&D credit provisions might have bipartisan support, but there's still the question of how to structure the offsets."