Charles Dharapak/AP Photo

As has been well documented, not everyone is so pleased that President Obama nominated former Senate colleague Chuck Hagel, a Republican, as the next secretary of defense.

Some of that has to do with Iran sanctions. Groups like the Republican Jewish Coalition and the Emergency Committee for Israel have noted that Hagel opposed them repeatedly when he was a senator - a big no-no among Israel hawks. ECI, meanwhile, has blasted Hagel for opposing military action against Iran as irresponsible.

Iran sanctions came up during the presidential race last year, as Mitt Romney and Republicans blasted Obama for going the multilateral route, eschewing U.S.-originated unilateral sanctions and instead gathering international support.

While one might assume that Hagel falls neatly in line with this Obama sanctions paradigm - multilateral good, unilateral less effective - it's worth noting that Hagel found himself on the opposite side of Iran-sanctions bills from Obama, Vice President Joe Biden, and new secretary of state nominee John Kerry.

A few notable instances, pointed out to ABC News by an Iran-sanctions expert:

• Hagel did not cosponsor the Iran Counter-Proliferation Act of 2007, which urged the president to designate the Revolutionary Guard Corps as a terrorist group; 72 senators, including Obama, Biden, and Kerry, cosponsored the bill.

• In July 2001, the Senate overwhelmingly extended the Iran and Libya Sanctions Act, which requires the president to "penalize" foreign companies that invest more than $20 million in Iran's energy sector. The extension passed 96-2. Hagel voted against it along with Republican Sen. Richard Lugar, who later enjoyed a good relationship with Obama as ranking member of the Senate Foreign Relations Committee. Biden and Kerry both voted for it.

• In August 2008, Hagel opposed the Comprehensive Iran Sanctions, Accountability and Divestment Act in the Senate Banking Committee, as it passed on a 19 - 2 vote. With Hagel no longer in the Senate, the measure passed 99-0 in 2010. Kerry voted for it, and Obama signed it that year.