Sen. Marco Rubio has come out swinging at President Obama’s decision to normalize relations with Cuba. The Florida Republican called it a “concession to tyranny.”

Rubio, a Cuban-American, deemed the move a “disgraceful” setback for both Americans and Cubans, writing in the Wall Street Journal that it marks a global “victory” for oppressive regimes.

The entire policy shift is based on the illusion—in fact, on the lie—that more commerce and access to money and goods will translate to political freedom for the Cuban people. Cuba already enjoys access to commerce, money and goods from other nations, and yet the Cuban people are still not free. They are not free because the regime—just as it does with every aspect of life—manipulates and controls to its own advantage all currency that flows into the island. More economic engagement with the U.S. means that the regime’s grip on power will be strengthened for decades to come—dashing the Cuban people’s hopes for freedom and democracy.

Rubio pointed to previous negotiations with Cuba, saying the possibility of improved relations had always been made clear, but that step would be taken only after a substantial shift in oppressive governing.

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This shift, Rubio notes, has not been made, yet Obama has illustrated a plan to normalize relations with little in return for both Cubans and Americans.

Obama justified the plan in his announcement yesterday by calling the current Cuban-American relationship an “outdated approach” that has “failed” to further U.S. interests.

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According to Rubio, this uneven trade-off further established Obama as the “single worst negotiator” he has seen in his lifetime.

To counteract this, Rubio announced he will do everything he can to “unravel” the president’s plan by aligning with congressional Republicans to block the Cuban ambassador nomination and funding for an embassy.

Beyond the political implications, Rubio believes Obama’s move is detrimental to U.S. relations abroad because of the “dangerous precedent” it could set in future negotiations.

The release of U.S. contractor Alan Gross who had been imprisoned in Cuba for five years was part of a separate deal, but marked similar repercussions to the senator.

President Obama made it clear that if you take an American hostage and are willing to hold him long enough, you may not only get your own prisoners released from U.S. jails—as three Cuban spies were—you may actually win lasting policy concessions from the U.S. as well. This precedent places a new price on the head of every American, and it gives rogue leaders around the world more clear-cut evidence of this president’s naïveté and his willingness to abandon fundamental principles in a desperate attempt to burnish his legacy.

Though Rubio lauded Gross’ release, he said the deal as a whole is just another concession to oppression that endangers Americans and Cubans alike.