On Tuesday, we looked at four big reasons why the assault weapons ban is very unlikely to pass in today's Congress.

Today, we're adding two more: the makeup of the House and former GOP supporters backing away from it.

When the 1994 assault weapons ban was approved, it passed by the narrowest of margins in the House, 216-214.

That was despite three big factors very much favoring passage:

1. Democrats had a 79-seat majority in the House

2. There was much higher public support for stricter gun control laws

3. It was significantly less restrictive than the current proposal

Yet even with those three things, 77 Democrats voted against the bill, and just 38 Republicans voted for it.

Today, Democrats are a 32-seat minority, meaning they need to have a completely united caucus and about 17 Republicans to jump on board.

In addition, just like the American public, the GOP caucus today is even more conservative on guns than it was back then. And perhaps most illustrative, even some Republicans who voted for the 1994 ban are not supporting today's version.

Just four Republicans who voted for the 1994 bill remain in Congress: Reps. Peter King (R-N.Y.), Ileana Ros-Lehtinen (R-Fla.), Chris Smith (R-N.J.) and Bill Young (R-Fla.).

Mitt Romney and Republican leaders made a campaign appearance in Miami in November 2011. From left are Reps. Mario Diaz-Balart and Ileana Ros-Lehtinen, former congressman  Lincoln Diaz-Balart and Romney. (JOE SKIPPER - REUTERS)

While King and Smith still support the ban, a spokesman for Ros-Lehtinen told The Fix on Wednesday that she will oppose it.

"Ros-Lehtinen used to support the ban, but she no longer does," spokesman Alex Cruz said.

Another "yes" vote on the 1994 ban, then-Rep. and now-Ohio Gov. John Kasich (R), has been noncommittal about whether he still supports such a measure.

The vote helped earn Kasich an "F" rating from the National Rifle Association (though that has since improved), and the NRA notably backed Democratic Gov. Ted Strickland over Kasich in 2010. Kasich said recently that he wouldn't urge members of Congress today to vote either way on the measure, but that the 1994 ban didn't work.

"My feeling is it wasn't effective," Kasich told 10TV.

(He also signed a bill in the weeks after the shootings in Newtown, Conn., that rolled back some gun restrictions in Ohio, drawing criticism from gun-control supporters.)

Moderate former congressman Chris Shays (R-Conn.), another "yes" for the 1994 ban who actually guided the bill through Congress, has also deemed the bill ineffective. After the theater shooting in Aurora, Colo., and during his unsuccessful Senate primary campaign last year, Shays said the ban "didn't achieve anything."

Shays told The Fix that such legislation amounts to simply getting rid of "the ugliest gun" in order to make people feel better.

“Do I think the assault weapons ban made a difference? Frankly, I don’t think it made a difference," Shays said. "The only reason to vote for it is public perception that you’re doing something meaningful."

Shays also said he could count 19 Democrats who lost elections because they supported the 1994 ban. “This vote is deadly for some members, and maybe times have changed, but it is a real deadly vote," Shays said.

The fact is, if an assault weapons ban could barely pass in a heavily Democratic House in 1994, a more restrictive version stands very little chance of passing in a Republican-controlled House in 2013.

And the fact that people like Ros-Lehtinen, Kasich and Shays have backed away from the such legislation proves it.