Corporate inversions are all the rage these days—over the past week and a half at least two large firms have announced plans to renounce their U.S. “citizenship.” Simply put, the U.S. corporate tax base is slowing leaking out of the U.S. to other countries. Most observers quite rightly blame our dysfunctional corporate income tax system for this problem, though there is no consensus on how to fix it—tax reform is unlikely in the near- or medium-term. As far as what to do about our eroding corporate tax base in the meantime, Democrats and Republicans are on completely different pages.

The main GOP position (and the position of others as well) was best summed up by John McKinnon and Kristina Peterson of the Wall Street Journal: “Many Republicans say inversions should be addressed as part of a broader overhaul of the tax code, noting that the U.S. has the highest corporate tax rate in the developed world.” There are two major problems with this position, however.

First, tax reform is not going to happen any time soon, but the tax base is eroding now. The GOP apparently wants tax reform, but when a serious tax reform plan was proposed by House Ways and Means Committee Chairman Dave Camp, the Speaker Boehner’s first comment was literally “Blah, blah, blah, blah.” This does not sound like a leader of a party that is serious about adopting tax reform anytime soon. Unless Congress passes a stopgap measure, it is likely a major proportion of the U.S. corporate tax base will have inverted before they can agree on a tax reform proposal.

Second, while the United States has one of the highest statutory corporate tax rates among developed countries, few firms actually pay that tax rate. Citizens for Tax Justice note that many large corporations, including GE, Verizon, and Boeing, have a negative tax rate. Additionally, it is noteworthy that two of the recent firms proposing to invert pay average tax rates of 22 percent (AbbVie) and 25 percent (Mylan), which are considerably below the 35 percent statutory corporate tax rate. The main point is the average corporate tax rate (what firms actually pay) is much lower than the statutory tax rate (what is written in the tax code) and not that much different from the average tax rate of many advanced economies.

Democrats, on the other hand, have proposed immediate fixes to preserve the tax base while Congress works on tax reform. Treasury Secretary Jack Lew called on Congress to clamp down on inversions. Rep. Sander Levin introduced H.R. 4679 and Sen. Carl Levin introduced S. 2360. Both bills would tighten the anti-inversion rules, thus making it more difficult (but not impossible) to invert. I should emphasize that these bills do not propose preventing large U.S. corporations from merging with small foreign corporations—they just make renouncing U.S. citizenship for tax purposes more difficult. Under current tax law, the new merged corporation is considered a foreign corporation for tax purposes if the shareholders of the large U.S. firm own less than 80 percent of the new merged firm. The proposals would, among other things, reduce the threshold to 50 percent.

And then there is tax reform. Many argue that corporate tax reform should be revenue-neutral—the tax base is broadened and the tax rate is reduced. This certainly has the effect of lowering the statutory tax rate, but does little to the average tax rate. Revenue-neutral tax reform will likely reduce the variance around the average, and there will be winners (firms with lower average tax rates) and losers (firms with higher average tax rates). But this by itself will not eliminate the incentive to invert—firms compare their average tax rate here to the average tax rate they would pay elsewhere. Consequently, other provisions will need to be adopted to stop inversions.