In a remarkable reversal, Sen. Marco Rubio (R-Fla.), who refused to support an urgently needed aid bill to Ukraine because Democrats had included reforms for the International Monetary Fund in the same bill, has dropped his opposition after criticism from Sen. John McCain (R-Ariz.) and other conservative voices including Right Turn. Last week Rubio’s staff vigorously defended Rubio’s opposition, expressing annoyance that the presidential hopeful was being singled out for criticism. Rubio had voiced arguments raised by right-wing groups like FreedomWorks that the reforms were somehow pro-Russian.

FILE - In this Feb. 5, 2014 file photo, Sen. Marco Rubio, R-Fla. testifies on Capitol Hill in Washington. The debate about whether to continue the dragnet surveillance of Americans’ phone records is highlighting divisions within the Democratic and Republican parties that could transform the politics of national security. While some leading Democrats have been reluctant to condemn the National Security Agency’s tactics, the GOP has begun to embrace a libertarian shift opposing the spy agency’s broad surveillance powers _ a striking departure from the aggressive national security policies that have defined the Republican Party for generations. (AP Photo/Lauren Victoria Burke, File) Sen. Marco Rubio (R-Fla.) (Lauren Victoria Burke/Associated Press)

In an op-ed for The Post he announces: “I  hope that events this week and Russia’s unrelenting aggression will lead Congress to move quickly next week to pass an assistance package to Ukraine and tough sanctions on Russia. Although I remain concerned by the proposed IMF reforms included in the legislation, the need to send a strong bipartisan message of solidarity to the people of Ukraine and a statement of resolve to Moscow far outweighs any misgivings I and others might have.”

Dan Runde and Conor Savoy at the Center for Strategic and International Studies (which will be hosting a forum to debunk objections to IMF reform today) have explained:

 [T]he United States would still retain its seat on the executive board, the largest voting share by a margin of 11 points, and a veto over any IMF actions that require a total of 85 percent of the shares to pass (i.e., admission of new members, increases in quotas, allocations of special drawing rights, and amendments to the IMF’s Articles of Agreement). Realistically, Europe suffers far more in this reallocation of voting shares and board reform than the United States does, and yet all European countries that are members of the G-20 have endorsed this reform effort. . . .

Ultimately, the IMF will likely play a major role in providing financial assistance to the new government in Kyiv, but it will take some persuading to do so given Ukraine’s past relationship with it. The United States will need to spend political capital with the IMF executive board in order to secure this funding. If the United States goes to the board as the only G-20 member state not to have formally endorsed IMF quota reform to argue for a large IMF package for Ukraine, our moral authority to do so will be weak. This is something that the rest of G-20 wants, it is something that the emerging markets and developing countries want, and it is something that our closest allies want. Our approval is the only thing that stands in the way of this reform being implemented. It will continue to be difficult for the U.S. representative at the IMF to seek support from other countries for important policies if this reform measure is not passed. Quota reform also offers Ukraine a doubling of its “quick draw” money based on the size of its quota under the new arrangement from $500 million to $1 billion—a sizeable difference. 

The about-face confirms a tension in Rubio’s staff and in his approach to critical issues. On one hand, he and his serious policy advisers favor a wonkish and hawkish foreign policy approach and enthusiastically support immigration reform. However, in what numerous conservative critics of Rubio have described to me as “over-compensation” or “over-correction” he chooses the most vociferous right-wing positions on most everything else, including the shutdown last year. At times — such as with the IMF flap and his opposition to authorization for use of force in Syria — these tendencies conflict, leaving conservative hawks and fellow senators exasperated.

More than anything, Rubio needs to develop the intestinal fortitude to ignore harping from those on the far-right who are unlikely to embrace him anyway; only if he can stand on principle and show he can lead on controversial issues will he project presidential gravitas. If he were simply another freshman senator, the room for error would be greater and missteps like this would go unnoticed. However, for someone who wants to be president, apparently, it suggests he has more maturing to do.