Depending on how it is structured, that could amount to a one-time boon for companies with large overseas profits, essentially rewarding past success rather than providing the incentives to invest in future growth.

“With repatriation at a lower rate, you’re not only providing a tax cut for choices that have already happened, but you’re rewarding choices that involved heavy tax avoidance and gaming of the tax system,” said Lily Batchelder, a law professor at New York University. “A lot of the reason so much money is socked away overseas is because of the ability of large multinationals to shift income on paper, so you’re kind of rewarding bad behavior.”

Business lobbyists argue that when companies return money home, they will use it to create jobs and investment in the United States. But the mid-2000s experience suggested they instead used the cash for a merger spree. And for companies that see promising opportunities, the booming stock market and low interest rates mean that capital is readily available on favorable terms already; it’s not clear why a company would invest in a new factory, for example, using repatriated overseas profits but not use money borrowed at a low interest rate by issuing bonds.

But the most interesting area of tension between changes that reward old behavior versus future behavior comes in how the corporate tax code handles capital investments by businesses.

Consider a company that spends $1 million on a piece of equipment expected to last 20 years. Currently, it can deduct the cost of investment spending gradually: in $50,000 annual chunks over two decades, unless covered by exceptions for certain equipment or for smaller businesses.

One idea, embraced by Republicans in the House but not those in the Senate, would be to allow companies to fully deduct capital expenses in the year they are incurred. Suddenly that company that spends $1 million on a piece of equipment could deduct the full million in the first year.

But this would be costly in terms of lost revenue to the Treasury, to the tune of a couple of trillion dollars over the next decade. And some people would rather that kind of money go toward reducing the corporate tax rate.