NEW YORK — With a deep split between Republicans and Democrats over abortion, activists on both sides of the debate say they expect the eventual presidential nominees to tackle the volatile topic more aggressively than in past elections.
Friction over the issue is likely to also surface in key Senate races. And the opposing camps will be further energized by Republican-led congressional investigations of Planned Parenthood and by Supreme Court consideration of tough antiabortion laws in Texas.
‘‘It’s an amazing convergence of events,’’ said Charmaine Yoest, chief executive of the antiabortion group Americans United for Life. ‘‘We haven’t seen a moment like this for 40 years.’’
In the presidential race, Democratic front-runner Hillary Clinton is a longtime defender of abortion rights and has voiced strong support for Planned Parenthood — a major provider of abortions, health screenings, and contraceptives — as it is assailed by antiabortion activists and Republican office-holders.
In contrast, nearly all of the GOP candidates favor overturning the Supreme Court’s 1973 Roe v. Wade decision, which legalized abortion nationwide. Some of the top contenders — including senators Ted Cruz and Marco Rubio — disapprove of abortions even in cases of rape and incest.
‘‘We may very well have the most extreme Republican presidential nominee since Roe — a nominee who’s not in favor of abortion in any possible way,’’ said Stephanie Schriock, the president of Emily’s List.
The organization, which supports female candidates who back abortion rights, says it is en route to breaking its fund-raising records. A similar claim is made by some anti-abortion political action groups.
One factor this year is the increased polarization of the two major parties. Only a handful of antiabortion Democrats and abortion-rights Republicans remain in Congress, and recent votes attempting to further limit abortions and halt federal funding to Planned Parenthood closely followed party lines.
Another difference: Republicans in the presidential field and in Congress seem more willing to take the offensive on abortion-related issues. Past nominees George W. Bush, John McCain, and Mitt Romney opposed abortion but were not as outspoken as some of the current GOP candidates.
‘‘If you don’t know how to handle this issue, you will be eviscerated,’’ said Marjorie Dannenfelser, president of the Susan B. Anthony List, which supports female candidates opposed to abortion.
As the campaign unfolds, other factors will help keep the issue in the spotlight.
The Supreme Court will be hearing arguments, probably in March, regarding a Texas law enacted in 2013 that would force numerous abortion clinics to close. One contested provision requires abortion facilities to be constructed like surgical centers; another says doctors performing abortions at clinics must have admitting privileges at a local hospital.
Abortion and Planned Parenthood are likely to surface as divisive issues in several Senate races. In New Hampshire, Democratic Governor Maggie Hassan, a supporter of abortion rights, hopes to unseat GOP incumbent Kelly Ayotte, who is endorsed by antiabortion groups and favors halting Planned Parenthood’s federal funding.