Roe v. Wade: decided on Jan. 22, 1973. Found that a Texas law that criminalized assisting women with abortions unconstitutional. Pictured: Jane Roe with lawyer Gloria Allred. (J. Scott Applewhite - AP)

A new NBC/WSJ poll finds that, on the 40th anniversary of the Supreme Court's Roe v. Wade decision, 70 percent of Americans want the landmark abortion rights ruling to stay. Only 24 percent would like Roe v. Wade to be overturned.

In the same Pew poll, 54 percent think abortion should be always legal or legal most of the time. Another 35 percent think abortion should be illegal but with exceptions; only 9 percent think it should be illegal with no exceptions. 

Thirty-nine percent of Americans approve of Roe in the survey while 18 percent disapprove; another 41 percent said they did not know enough to have an opinion. A recent Pew survey found that while 62 percent of Americans correctly say that the case dealt with abortion, a majority of those under 30 do not know what Roe was about.

The same poll found that Republicans were evenly divided on overturning Roe. Large majorities of Democrats and independents were against overturning the decision.

But the issue was more critical for opponents of abortion than it was for supporters: 74 percent of those who support overturning Roe consider abortion a “crucial issue” or “one of many crucial issues.” Only 31 percent of Roe supporters said the same.

Gallup surveys on abortion are pretty consistent over time, with a majority saying abortion should be legal but only under certain circumstances.