U.S. Sen. Michael Bennet backed the president’s Iran nuclear agreement Friday despite an onslaught of opposition to the controversial treaty in Colorado and across the nation.

In a press release sent Friday afternoon, Bennet said after careful consideration he determined this deal is better than the alternative.

“This agreement is more likely to prevent Iran from acquiring a nuclear weapon than the plausible alternatives,” Bennet said.

The issue has become a political lightning rod. Millions of dollars are being spent on TV ads opposing the Iran deal. Bennet, a Democrat from Denver, was a key vote in the Senate on the issue as President Barack Obama needed to secure 34 senators supporting his position to avoid a veto override. It’s still unclear if opponents of the measure have enough votes in the Senate to pass the resolution opposing the Iran deal, but if that group can get it passed, the president’s veto will likely stand.

One potential opponent for Bennet decided to enter the 2016 race for Senate based on his position on this issue.

“This might be the seminal issue of the last couple of decades from a foreign policy standpoint,” said Robert Blaha, a Colorado Springs businessman who said he would run for Senate if Bennet supported the deal. “This issue really is one of the most enormous issues that America has struggled with in decades, and to watch how this lackluster senator stuck his finger in the wind and waffled back and forth and acted like he was doing an assessment is truly pitiful.”

Bennet says in his statement he spent a great deal of time assessing the deal that will lift sanctions against Iran in exchange for broader international scrutiny and control over the Middle-Eastern country’s nuclear capabilities.

He also is proposing legislation that he said would “address the accumulated shortcomings of our policies towards Iran, and to strengthen the agreement.”

That legislation would do things like require tracking of the “incremental resources that Iran obtains from sanctions relief;” provide Israel with deterrence support to ensure Iran cannot hide covert systems and facilities; and set up clear consequences for Iran if the country “cheats on this deal.”

It is co-sponsored by Sen. Ben Cardin, D-Md., who announced Friday that he is opposed to the president’s deal.