PORTLAND — Maine Sens. Susan Collins and Olympia Snowe are joining with a third centrist Republican to request that the White House continue working with Congress on strengthening the nation’s cybersecurity laws rather than issue an executive order.

“The ramifications of a national cybersecurity policy for the public and private sectors are significant and deserve the transparency and legitimacy that can be achieved only though the legislative process,” Collins, Snowe and Sen. Richard Lugar wrote in a letter Wednesday to President Barack Obama.

Cybersecurity is among the long list of issues that Congress punted until after the election despite dire warnings from top defense officials and the Obama administration about the inadequacy of the nation’s computer defenses.

Security experts and lawmakers working on the issue have raised alarms about the possibility of large-scale computer attacks that could disrupt the critical infrastructure networks supporting banking, the power grid and communications. They have warned that the next major terrorist attack on the U.S. could be computer-borne.

Frustrated with congressional inaction, the White House has been drafting an executive order to deal with the issue. According to the Associated Press, which obtained a copy of the draft in September, the White House is considering voluntary security compliance standards for companies, a new cybersecurity council within the Department of Homeland Security and a process for proposing new federal regulations.

Collins was co-author of a bipartisan bill that also emphasized voluntary compliance rather than government-imposed security standards, a concession aimed at overcoming opposition from powerful business interests.

But the legislation still stalled in the Senate. Afterward, Collins and Sen. Joseph Lieberman of Connecticut – also a bill co-sponsor – rebuked the Senate’s failure to act in the face of so many warnings from defense officials, with Collins calling it “a shameful day.”

Despite the ongoing concerns, Collins, Snowe and Lugar wrote to Obama this week that it would be “a mistake” to attempt to handle the issue via executive order. They said only Congress can ensure that privacy protections, companies’ liability concerns and other issues are addressed properly, they wrote.

“As members who have worked hard to advance cybersecurity legislation in the Senate, we believe the legislative process remains the best way to build lasting consensus on an issue that is vital to our national security and our economic prosperity,” Snowe, Collins and Lugar wrote.

“We share your frustration that Congress has not yet completed its work on this legislation, but we remain committed to the legislative process and urge you to continue to work with Congress, rather than acting unilaterally through an executive order.”

Cybersecurity has remained a hot topic in Washington ever since supporters of the Senate bill failed to get enough votes to move the issue forward.

The White House has declared October as National Cyber Security Awareness Month in what some saw as a precursor to the executive order.

Also this month, dueling panel discussions were held in Washington during the same week. Speaking at an Oct. 1 discussion hosted by The Wilson Center and National Public Radio, Collins said she feared an executive order could give people a false sense of security that the issue has been addressed.

The American Civil Liberties Union, which has expressed serious concerns about privacy implications of earlier versions of the Senate bill, is raising the alarm about an executive order.

During the Oct. 1 panel discussion, ACLU Executive Director Anthony Romero said any action by the White House regarding the collection of personal data is worrisome. He explained that while an executive order may be issued “for good reasons” by one administration, subsequent administrations could use those powers “for bad reasons.”

“It’s misguided,” Romero said. “It might … backfire on us and it is just not going to solve the problem and the long-term issue.”