Democratic Gov. Janet Mills will allow a bill requiring a three-day waiting period to purchase firearms to become law without her signature and she is also vetoing a bill that would ban so-called bump stocks.
Both proposals narrowly cleared the Democratic-controlled House and Senate and were among a slate of proposals that the majority party advanced in response to the Lewiston shootings last fall.
In a statement the governor said that she was deeply conflicted about the waiting-period bill, which supporters said would help prevent suicides.
"In carefully considering all the arguments, I have decided to allow this bill to become law," she said. "I do so, however, with some caveats and concerns and with the hope that it can be implemented to accomplish its intended goal of preventing suicide by firearm without overburdening our outdoor sports economy and the rights of responsible gun owners and dealers to engage in lawful and constitutionally protected activities."
Opponents argued that the bill would limit the ability of people to quickly purchase a gun to defend themselves and some gun-rights groups are promising to challenge its constitutionality as their counterparts have in other states.
Mills noted the prospect of a legal challenge in her statement.
Mills vetoed the ban on bump stocks, which are devices that can increase the rate of fire on semi-automatic rifles.
The governor argued in her veto letter that the definition of affected conversion devices is overly broad and ambiguous and might inadvertently include devices that don't actually allow some guns to fire like an automatic weapon.
Sen. Anne Carney, D-Cape Elizabeth, sponsored the bill, saying it aligns with a rule enacted by former President Donald Trump after a bump stock device was used by the gunman who killed 60 people in Las Vegas in 2017, the deadliest mass shooting in U.S. history. In a statement, she said the state should "balance a theoretical concern about unintended consequences against the very real public safety concerns rapid-fire devices create."
The legislature will have a chance to override the governor's veto, but it's unlikely that enough lawmakers will do so.
The proposal narrowly cleared the Legislature and two-thirds of the House and Senate are needed to override a veto.
Maine now will become the 10th state to require some kind of waiting period for firearms purchases. The law is the second passed this session in response to the Lewiston mass shootings.
The governor on Friday signed her own bill to expand background checks to advertised gun sales and create a network of crisis prevention centers. Her bill also tweaks Maine's yellow flag law, which allows law enforcement to initiate a process to confiscate the firearms of a person deemed a threat to themselves or others pending a mental health evaluation.
A bill that would create a path for family members or law enforcement to initiate such a process without a mental health evaluation was introduced late in the session and never came up for a vote in the House and Senate.
