WASHINGTON -- Likely GOP presidential hopefuls are piggybacking onto a controversial letter sent to Iranian leaders this week by Senate Republicans.
Forty-seven GOP senators sparked intense criticism by suggesting in a missive to Tehran that any nuclear agreement with the Obama administration would not be constitutionally binding, because a future U.S. president or Congress could take steps to undo the deal.
Not to be outdone by their potential GOP rivals in the Senate -- Rand Paul (Ky.), Ted Cruz (Texas) and Marco Rubio (Fla.), who all signed the letter -- Louisiana Gov. Bobby Jindal and former Texas Gov. Rick Perry both announced their support for the letter on Tuesday.
The office of Sen. Tom Cotton (R-Ark.), the author of the letter, announced later on Tuesday that Jindal's name had been added.
Democrats condemned the move as undermining President Barack Obama's authority to negotiate with foreign governments. Vice President Joe Biden said in a caustic statement Monday night that the letter was "beneath the dignity of an institution I revere."
Jindal took to Twitter to call on the vice president to apologize to Cotton.
"He wore the boots in Iraq. He's earned our attention, not your insults," Jindal said.
The governor then urged other potential 2016 candidates to join him by signing the letter.
"Make no mistake – any Iran deal that President Obama makes is not binding on a future president," he said.
Former Pennsylvania Sen. Rick Santorum (R), who has also made moves toward a bid for the White House, praised Cotton for drafting the letter. "I am grateful that the U.S. Senate is exercising their constitutional prerogative to stop this reckless diplomacy by the Obama-Kerry-Clinton foreign policy team," he said in a statement.
Neither Former Florida Gov. Jeb Bush (R), Wisconsin Gov. Scott Walker (R), or former Hewlett Packard CEO Carly Fiorina went so far as to explicitly endorse Cotton's letter. But all three spoke supportively of Congress' role in the process.
Bush, considered an early frontrunner for the nomination, said in a statement that Republicans "would not have been put in this position had the administration consulted regularly with them rather than ignoring their input."
Walker tweeted Tuesday that unless Obama was "prepared to submit the Iran deal for Congressional approval, the next president should not be bound by it."
And Fiorina, another Republican who is weighing a run for president, urged Republicans to find a "bi-partisan, veto proof majority" of senators who will "demand their rightful and constitutional place in the negotiation approval process."
"If I choose to run for President and were elected, I would always do what is necessary to protect our national security," Fiorina said in a statement. "Iran has never agreed to full and unfettered inspections. They must or we cannot trust anything they sign. Until they are prepared to open their nuclear facilities to full and unfettered UN-sanctioned inspections and demonstrate that they are willing to halt uranium enrichment, any deal will not be in our national security interest. Republicans need to continue to work toward a bi-partisan, veto proof majority of Senators who will demand their rightful and constitutional place in the negotiation approval process."
This post has been updated with additional statements from likely presidential candidates.