Rep. Brad Sherman (D-Calif.) last week launched his latest push to clarify and modernize the lines of presidential succession in the wake of a major terrorist attack or other catastrophic event.

Sherman introduced a similar measure in the 109th Congress, but now that he is in the majority, he hopes to pick up important allies in his campaign to overhaul what he sees as a dangerously outdated law.

The bill would require presidential and vice presidential nominees to name “successors” to take over should the original nominees die or be permanently incapacitated between the end of the presidential convention and the casting of electoral votes.

The bill also would place the U.S. ambassadors to the United Nations, Great Britain, Russia, China and France after the secretary of Homeland Security in the line of presidential succession.

Cabinet members are routinely in Washington, D.C., and, should a catastrophic event occur here, it is possible all would be killed at once, Sherman said, adding that ambassadors, on the other hand, typically are out of the country.

Sherman compared the provisions in the bill to the concrete barriers put up around the Capitol, White House and other important government buildings.

“The fact is, you want to have as much protection for our democratic institutions from terrorists that you can possibly get,” Sherman said. “We make [workers] truck around these heavy barriers and scrape their hands and wrench their backs. The least we can do is build a strong structure.”

Sherman officially introduced the bill, the Presidential Succession Act of 2007, in the House on Wednesday. It was referred to the Judiciary Committee.

While a similar measure floundered in the previous session, Sherman said he thinks it has a chance this time, primarily because he is in a position to move it forward.

“I’ve gotten myself on the Judiciary Committee,” Sherman said. “I expect to be on the relevant subcommittee, because I need to push this bill. … There is nothing more important, if we face a national crisis or terrorist attack, than knowing who our president is.”

The bill also would have an outgoing president nominate the incoming president’s Cabinet choices, a move that would require cooperation between administrations but would better secure the succession lines, as Cabinet secretaries are so high up on the list.

The current line of succession would remain intact. But if both the Speaker and the Senate President Pro Tem die at the same time, the highest-level surviving Cabinet member would become president.

Sherman consistently has introduced legislation designed to address continuity issues. Sherman admitted it is difficult to get attention for such measures, in part because there isn’t anyone who actively lobbies on the issue.

“Until the last couple of weeks, we had a majority that just didn’t care,” Sherman said. “There wasn’t anybody on K Street, so they didn’t focus on it, and I hope we’ll do better than that.”

Passing such legislation should be a priority, Sherman said. When John Wilkes Booth planned his assassination on then-President Abraham Lincoln, he also wanted to kill the vice president and other government leaders, Sherman said.

“We should expect that [Osama] bin Laden is just as ambitious,” he said.