Fifty-five percent of Americans support legislative efforts to legalize marijuana, according to a new NBC News/Wall Street Journal poll. Those respondents would back similar laws to the ones on the books in Colorado and Washington state, where adults over the age of 21 are permitted to possess limited amounts of marijuana for personal use.

Chuck Todd talks to NORML's Allen St. Pierre about the history and future of marijuana legalization.

Almost a quarter of the country does not approve of laws to legalize marijuana, but would tolerate them. Those Americans (24 percent) would not actively seek the repeal of laws backed by state voters and state legislatures.

The numbers reflect a gradual sea change in the public's views toward marijuana, and the laws that govern what federal law currently deems a "Schedule I" drug, worthy of the government's strictest treatment.

"I don’t think it is more dangerous than alcohol," President Barack Obama, who opposes legalization, said earlier this month in an interview with The New Yorker magazine. New York Democratic Sen. Charles Schumer said Monday on MSNBC that letting Colorado and Washington to experiment with new marijuana laws was a "good idea."

And even a stalwart conservatives like Texas Gov. Rick Perry boasted last week of initiating a path toward decriminalization of marijuana in his state during remarks at the World Economic Forum in Switzerland.

Additional states could be poised to approve more lax marijuana laws come this fall. Florida’s Supreme Court on Monday approved a medical marijuana ballot initiative for this November, and petitioners in Washington, D.C., are hoping to add a legalization measure to the federal city’s ballot this fall as well.

But the politics of marijuana are still far from settled. The issue is fraught with divisions along party identification and age groups, and gender, race and geography all shape the issue, too.

Americans aged 18 to 34, for instance, broadly favor legal marijuana by a whopping 49-point margin. Americans over the age of 65, by contrast, oppose legalizing weed, 59 percent to 38 percent. The age groups in between are largely split on the question of legalization.

Americans also split on marijuana by party. Democrats favor pot legalization by a 34-point margin, while Republicans oppose it by 23 points. Among independents, 60 percent favor legalization, while 39 percent oppose it.

In a recent interview that has raised some eyebrows, President Obama weighed in on marijuana, saying that while he still discourages use of the substance, he believes it is no worse than alcohol.

Regionally, support for legalization runs higher in the West, where Colorado and Washington took the lead in voting for legalization and where California spearheaded an informal economy built on marijuana cultivation. Americans in Midwestern states, by comparison, are less sanguine about legalization.

The issue is also shaped by a slight gender gap: men favor legalization much more strongly than women. A majority of women (51 percent) favor legalization, versus 47 percent of women who oppose it. Fifty-nine percent of men favor legalization, though, and just 39 percent oppose it.

White Americans are also less supportive of legalization proposals (favoring them by a 6-point margin) as compared to African American and Hispanic respondents, who favor legalization by 19 and 17-point margins, respectively.

The NBC News/Wall Street Journal poll was conducted Jan. 22-25 and has a plus-minus 3.5 percent margin of error for its sample of all respondents. Subsamples have larger margins of error.