PRINCETON, NJ -- Forty years after the Supreme Court issued its opinion in Roe v. Wade, significantly more Americans want the landmark abortion decision kept in place rather than overturned, 53% to 29%. Another 18% have no opinion, the highest level of uncertainty Gallup has recorded on this question in trends dating to 1989.

The latest results are from a USA Today/Gallup poll conducted Dec. 27-30.

In the broadest sense, Americans' reaction to Roe v. Wade has been consistent for the past few decades. A majority have always opposed overturning the decision, while roughly a third favor doing so. However, in 2006, as the percentage of Americans with no opinion about the status of Roe v. Wade increased, the percentage opposed to overturning it dropped below 60%, and has since remained in that lower range. This year, with a record-high 18% unsure, the percentage wanting it overturned fell below 30% for only the third time since 1989.

Gallup trends indicate that the increase in public uncertainty about overturning Roe v. Wade is largely the result of a growing percentage of young adults aged 18 to 29 expressing no opinion. This suggests that the generation born entirely after Roe became law has had less exposure to information about the decision than those who lived through the original decision, or were at least old enough to witness some of the major abortion debates during the 1980s and '90s, such as those involving President Ronald Reagan's nomination of Robert Bork to the Supreme Court in 1987 and reaction to the high court's Planned Parenthood of Southeastern Pennsylvania v. Casey decision in 1992.

Americans Maintain Middle-of-the-Road Position on Legality

The same Dec. 27-30 poll also updated Gallup's longest-running trend on abortion attitudes. This asks Americans if abortion should be "legal under any circumstances," "legal only under certain circumstances," or "illegal in all circumstances." Currently, 52% favor the middle position, while 28% say it should always be legal and 18% never legal. Views on this have been fairly stable over the past four years.

These results conform to Gallup polling since 1975, which has consistently found a majority or plurality of Americans favoring the middle position. At the same time, there have been notable shifts over the years in the balance of support for the more absolute views at either end of the abortion-policy spectrum.

In the initial years after the Roe v. Wade decision, roughly equal percentages of Americans said abortion should be legal under any circumstances vs. illegal in all circumstances, about 20% each.

In the 1980s, attitudes gradually shifted toward the solid pro-abortion rights position, so that by 1990, those who favored legalization in all cases outnumbered those who would oppose all abortions by a more than 2-to-1 margin. This trend peaked in June 1992, with 34% saying abortion should be legal in all cases and 13% saying it should be completely banned.

In July 1996, a relatively abrupt shift occurred: the percentage saying abortion should be legal in all cases dropped from 31% to 25%. This coincided with a then-new national debate over partial-birth abortion playing out in Congress. The percentage of Americans in favor of making abortion illegal didn't increase at that time, but more people took the middle position -- saying it should be legal under certain circumstances (peaking at 61% in 1997).

Today's views are neither as conservative as they were in 1975 nor as liberal as they were in the early 1990s, but are about average for the entire time frame.

Americans Frown on Second- and Third-Trimester Abortions

Much of the reason for Americans' ambivalence about abortion is evident in their views toward the legality of the procedure during each trimester of pregnancy. This also happens to be the framework used in the Roe v. Wade decision, which says that the interests of the mother are paramount in first trimester, but that the state has an interest in protecting the fetus in "the stage subsequent to viability," or the third trimester.

A solid majority of Americans (61%) believe abortion should generally be legal in the first three months of pregnancy, while 31% disagree. However support drops off sharply, to 27%, for second-trimester abortions, and further still, to 14%, for third-trimester abortions. Gallup has found this pattern each time it has asked this question since 1996, indicating that Americans attach much greater value to the fetus as it approaches viability, starting in the second trimester.

Since 1995, Gallup has asked Americans to summarize their own position on abortion using the same "pro-choice" and "pro-life" terms that the advocacy groups lined up on each side of the abortion battle have traditionally used to describe themselves. Twice since 2009, Gallup has found "pro-life" Americans significantly outnumbering "pro-choice" Americans; however, for the most part, Americans have been closely divided in their identification with the terms. That is also seen today, as 48% call themselves "pro-choice" and 44% "pro-life."

Gallup's full trend on this measure indicates that the "pro-choice" label was significantly more popular in 1995; however, at the same time that support for the broad-based legality of abortion stumbled in 1996, coincident with congressional debate over partial-birth abortion, support for the "pro-choice" position fell, and has since remained lower.

Americans' preferences for the "pro-choice" vs. "pro-life" terms vary greatly by political party and ideology, but also by demographic characteristics. Americans with no religious affiliation and self-described liberals are the most likely to call themselves "pro-choice," with roughly eight in 10 choosing this label. Postgraduates and high-income earners are nearly as oriented to the pro-choice position as are Democrats, followed by Easterners, suburbanites, and young adults.

On the other end of the spectrum, Protestants, low-income Americans, adults with no college education, and Southerners join Republicans and conservatives as the least "pro-choice."

Notably, both men and women are close to the national average in their preferred label.

Bottom Line

Roe v. Wade is synonymous with abortion rights. Thus it follows that because the majority of Americans favor keeping abortion legal, at least under certain circumstances, the majority wants to see Roe continue to be the law of the land. However, as clarified in the Supreme Court's 1992 Casey decision, Roe allows states to place limits on late-term abortions, and that would appear to fit with Americans' attitudes as well. The vast majority oppose abortions not only in the third trimester, but also the second. Still, this is not to suggest the absence of controversy surrounding abortion. That is evident in the nearly even split between Americans calling themselves "pro-choice" and those calling themselves "pro-life," and the wide variation in attachment to these terms by the political left and right. This deep political division is likely to surface in the coming years with several Supreme Court justices possibly nearing retirement, setting off fresh debate over Roe's future.