Yesterday, deep in the Brazilian hinterland, 33 leaders from Latin America and the Caribbean called on President-elect Obama to end the embargo on Cuba.

Their unequivocal call to end a policy that the UN General Assembly has voted against 16 times, that has failed for 50 years to achieve its objective, and that amounts to a self-imposed barrier to entering into a 21st century relationship with the rest of the Hemisphere -- seems to me to be a strategic no-brainer for the incoming administration.

So what is the price of leadership in the Western Hemisphere? It's a trick question, really. In dollar terms, the cost of renovating Hemispheric relations is practically nil. Ending the embargo is the right thing to do, still leaves us plenty of carrots and sticks for negotiations with Cuba, and costs the Treasury nothing. In fact, given the explosion of trade with the Southern United States that would accompany the change in status, America would profit from the move.

What we gain, on the other hand, is priceless. Over the past two decades, the embargo has been more of a wall separating the U.S. from Latin America than it has been a siege of Cuba. The lack of trust rooted in the senseless persistence of the embargo combined with our Cold War support for right-wing governments, our misguided insistence on the "Washington Consensus" and now our unwillingness to recognize that our immigration problem is a symptom of the lack of economic opportunity in sending countries is the biggest barrier to progress in the region.

What is important to note, however, is that the "ask" from these Latin American nations is decisive, not incremental. President-elect Obama's campaign promises, calibrated to appeal to an demographic shift within Southern Florida that was incompletely understood until the election results arrived, those promises are not enough to get the nations of Latin America to embrace the United States once again.

In the second week of April, then-President Obama will have the opportunity to address the OAS Summit of the Americas in Trinidad. If he does not make his move before then, the president must take the opportunity to answer this call from his fellow heads of state.

This will be one of the greatest tests for Hillary Clinton as Secretary of State. She will have to put her family's record on Cuba policy aside, aggressively pursue the national interest and prepare the way for then-President Obama to claim a major foreign policy victory. She can be the architect, but Mr. Obama must be seen as the author. What we need is a clear signal from within Mr. Obama's inner circle that it is time for a decisive shift in policy, one that can capture the goodwill and imagination of the nations of the Western Hemisphere.

Mrs. Clinton's challenge will be to hear the signal and prioritize an easy win in the midst of all the foreign policy and economic crisis management.