Matthew Staver/Bloomberg/Getty Images

Americans are split on spliff.

Marijuana, that is. Forty-nine percent in a new ABC News/Washington Post poll support legalizing small amounts of the drug for personal use. Almost exactly the same number, 48 percent, are opposed.

Support for legalization is numerically at a new high in ABC/Post polls, albeit only by a single percentage point from its level slightly more than a year ago, and up dramatically from its lows in the mid-1980s and well into the 1990s.

At the same time, strength of sentiment continues to weigh against the weed. Thirty-six percent "strongly" oppose its legalization, more than the 28 percent who strongly support it.

This poll, produced for ABC by Langer Research Associates, finds several sharp contrasts on the issue among groups, notably by age, political party identification and ideology.

See PDF with full results, charts and tables here.

Americans 65 or older are half as likely to approve of legalization as are those age 18 to 64 - 27 vs. 54 percent. And 59 percent of the elderly disapprove strongly. Support peaks among 18- to 39-year-olds, at 59 percent, including 37 percent who strongly support the idea.

In partisan terms, 57 percent of Democrats and 50 percent of independents support legalization, compared with 37 percent of Republicans. Adding in ideology, the range stretches from 69 percent support among liberal Democrats to 28 percent among conservative Republicans.

This poll finds few differences across other groups, including by race, education, sex, region or the presence of children in the home.

Other polls in the past year have varied on views of legalization, with support ranging from 45 to 58 percent, indicating that attitudes on the issue may be unsettled, and perhaps particularly sensitive to question wording, as public policy on the issue evolves. As it has since 1985, the ABC/Post survey asks if Americans "support or oppose legalizing the possession of small amounts of marijuana for personal use."

Twenty-three states have decriminalized possession of marijuana or allow its medical use, and Washington and Colorado have legalized its sale and possession of one ounce or less for personal use.

METHODOLOGY - This ABC News/Washington Post poll was conducted by landline and cell phone Jan. 8-12, 2014, in English and Spanish, among a random national sample of 1,011 adults. Results have a margin of sampling error of 3.5 points. The survey was produced for ABC News by Langer Research Associates of New York, N.Y.