It depends on how you define "ban".
Gallup polls on the issue show a country equally divided (within the margin of error) between "pro-choice" and "pro-life" camps since the late 1990's.
Though, when given a three-way choice between total legality, total illegality, and a compromise "under certain circumstances" option, a plurality of people choose the compromise option.
But what circumstances are those, exactly?
According to the same article, a majority of Americans (in the most recent poll) believe that abortion should be legal:
- In the first trimester of pregnancy (60%)
- When the woman's life is endangered (83%/75% for first/third trimester)
- When the pregnancy was caused by rape or incest (77%/52%)
should not be legal:
- In the second (65%) or third (81%) trimester of pregnancy
- When the woman does not want the child for any reason (53%/77% for first/third trimester)
and legal only early in pregnancy for:
- When the child would be born mentally disabled (56% legal first trimester / 61% illegal third trimester)
- When the child would be born with a life-threatening illness (67%/49%)
- When the child would be born with Down Syndrome (49%/68%)
Now, let's look at statistics on abortions performed in the US, and see how many would have been legal if it were put up to a national popular vote.
According to the CDC (2019):
A total of 629,898 abortions for 2019 were reported to CDC from 49 reporting areas. Among 48 reporting areas with data each year during 2010–2019, in 2019, a total of 625,346 abortions were reported, the abortion rate was 11.4 abortions per 1,000 women aged 15–44 years, and the abortion ratio was 195 abortions per 1,000 live births [i.e., there were 3.23 million live births].
During 2010–2019, the percentage of abortions performed at >13 weeks’ gestation remained consistently low (≤9.0%). In 2019, the highest proportion of abortions were performed by surgical abortion at ≤13 weeks’ gestation (49.0%), followed by early medical abortion at ≤9 weeks’ gestation (42.3%), surgical abortion at >13 weeks’ gestation (7.2%), and medical abortion at >9 weeks’ gestation (1.4%); all other methods were uncommon (<0.1%).
IOW, 91.3% of abortions (surgical + medical) are performed in the first trimester. So a ban on second and third trimester abortions would affect only 8.7% (around 55,000) of them.
However, a different picture is painted when we look at abortions by reason:
According to the Guttmacher Institute (2004) (sorry, I can't find more recent data right now), the breakdown of abortions by most important reason for having them (Table 3, page 114 in linked document) are:
- Not ready for a(nother) child/timing is wrong: 25%
- Can’t afford a baby now: 23%
- Have completed my childbearing/have other people depending on me/children are grown: 19%
- Don’t want to be a single mother/am having relationship problems: 8%
- Would interfere with education or career plans: 4%
- Physical problem with my health: 4%
- Possible problems affecting the health of the fetus: 3%
- Was a victim of rape: <0.5%
- Husband or partner wants me to have an abortion: <0.5%
- Parents want me to have an abortion: <0.5%
- Don’t want people to know I had sex or got pregnant: <0.5%
- Other: 6%
"Health" reasons (maternal and fetal combined) account for a mere 7% of abortions. And rape is less than half of a percent. IOW, at least 92.5% of abortions are not for the "hard cases" in which there is overwhelming support for legality. And it is these abortions which are at stake in the debate.
Also note that many of the restrictions that states have been enacting enjoy widespread popular support. From the same Gallup article linked earlier, a majority would favor:
- A law requiring women seeking abortions to wait 24 hours before having the procedure done (69%)
- A law requiring women under 18 to get parental consent for any abortion (71%)
- A law banning "partial birth abortion" except in cases necessary to save the life of the mother (64%)
- A law requiring doctors to inform patients about certain possible risks of abortion before performing the procedure (87%)
- A law requiring women seeking an abortion to be shown an ultrasound image of her fetus at least 24 hours before the procedure (50%)
- A law requiring that the husband of a married woman be notified if she decides to have an abortion (64%)
- A law requiring doctors to inform patients about alternatives to abortion before performing the procedure (88%)
So, although only 19% of Americans support a complete ban on abortion, a majority do want significant restrictions on the practice.