Suppose that during the previous administration the Democrats had opposed President Bush's efforts to protect airplanes from would-be bombers and had blocked his strategy to keep nuclear weapons out of terrorists' hands.

It's a safe bet Bush would charge, as he did more than once during his presidency, that Democrats are "not interested in the security of the American people." Other Republicans would no doubt be running ads juxtaposing Democrats with Osama bin Laden, or alleging, as they did then, that Democrats are giving "comfort to America's enemies."

Yet right now, Republicans are providing the comfort. They are objecting loudly to new airport security measures designed to detect bombs hidden under clothing. And they are blocking a Senate vote on a treaty with Russia that is critical to securing loose nukes and keeping Iran from gaining the bomb.

For Democrats, the opposition's gamesmanship with the security should present an opportunity. Republicans seem to have entered a post-post-9/11 era, in which national security is no longer a higher priority than their interest in undermining President Obama. There's no need to resort to the demagoguery once used against Democrats, but neither would it hurt the White House and congressional Democrats to point out that their opponents are trying to weaken Americans' security.

Let's start with START, the proposed nuclear pact with Russia that Senate Republicans such as Jon Kyl (Ariz.) are attempting to derail, at least until the next Congress. Since the expiration of the previous START treaty last December, there have been no U.S. inspectors in Russia to keep an eye on the country's thousands of nuclear warheads. If the Senate doesn't come up with the 67 votes needed for ratification, says Travis Sharp of the Center for a New American Security, there's a risk Russia will retaliate by removing its logistical support for the U.S. war in Afghanistan, abandoning its cooperation in preventing nuclear proliferation, and thwarting U.S. efforts to keep Iran from gaining nuclear weapons.

But don't take his word for it. Listen to Richard Lugar, top Republican on the Senate Foreign Relations committee and one man who still puts the national interest above political considerations. "We're talking today about the national security of the United States of America," he pleaded on Wednesday. "[T]his treaty must be ratified and be ratified in this session of the Congress.... We're talking about thousands of warheads that are still there, an existential problem for our country. To temporize at this point I think is inexcusable."

Or listen to Bob Gates, the Bush/Obama defense secretary. "The new START treaty has the unanimous support of America's military leadership," he wrote in the Wall Street Journal, calling for a strong bipartisan majority to support the treaty because of "the security it provides to the American people."

To borrow Bush's phrase, are Republicans not interested in the security of the American people?

Then there's the backlash over the new imaging and pat-downs being used to screen airport passengers for explosives. A CBS News poll found that 81 percent of Americans favor use of the new imaging machines, but Republican lawmakers feel otherwise.

In the House, Rep. Ron Paul (Tex.) has already introduced legislation rescinding the new security. Meanwhile, Republican senators, rediscovering their inner civil libertarians, this week took turns criticizing Transportation Security Administration chief John Pistole over the administration's tightened security.

"I wouldn't want my wife to be touched in the way that these folks are being touched. I wouldn't want to be touched that way," said Sen. George LeMieux (Fla.). "I think weve gone too far."

Sen. Mike Johanns (Neb.) warned of a "tipping point" against security screening. "Does that worry you, that maybe we're at a point here where... people just thing you've overstepped?"

Pistole reminded Johanns that "the threats are real."

"I'm thinking nothing's going to change," Johanns complained.

Pistole's response should shame Johanns and his colleagues. "If your question is, do I understand the sensitivities of people? Yes. If you're asking, am I going to change the policies? No, because I think that it is being informed by the latest intelligence, the latest efforts by terrorists to kill our people in the air. No, I'm not going to change those policies."

This may be the post-post-9/11 era, but Pistole, a career FBI guy, is still interested in the security of the American people. Are Republicans?

danamilbank@washpost.com

Dana Milbank was online to chat with Post readers at 11:30 a.m. Friday, Nov. 19. You can read a trasncript of the discussion here.