WASHINGTON - As the nation heads into a presidential election year, the Supreme Court is set to decide a half-dozen politically charged cases in 2016 on such topics as abortion, affirmative action, contraceptives and immigration.

In several cases, conservatives are hoping the high court will shift current law to the right or block President Barack Obama’s policies, while liberals are defending the status quo.

But with justices closely split along ideological lines, the cases are likely to yield a series of 5-4 decisions and make clear the next president’s appointees could tip the law sharply to the right or left.

Here are the major cases due for decision by June 2016.

Abortion

The court will decide whether Texas can enforce two regulations that would force about three-fourths of the state’s abortion clinics to shut down.

One measure requires clinics to use only doctors with admitting privileges at a nearby hospital. A second requires abortion facilities to match the standards of an outpatient surgical center.

The first question before the court is whether these regulations will protect the health of women - as state lawmakers assert - or hinder reproductive care “by drastically reducing access to safe and legal abortion” in large parts of Texas, as abortion-rights advocates contend.

In the background is a larger question about the nature of abortion rights set out in the Roe vs. Wade decision: Is it a constitutional right that trumps state regulations that may interfere with a woman’s choice, or is it a limited right subject to restriction? The case of Whole Woman’s Health vs. Cole will be argued March 2.

Affirmative action

The court’s conservatives believe the Constitution and the civil rights laws forbid schools and colleges from admitting students based on their race, and they would like to strike down affirmative action policies that favor some applicants over others based on their race or ethnicity.

Justice Anthony M. Kennedy, seen as the swing vote, has agreed with conservatives in the past and condemned admissions policies that set “numerical goals indistinguishable from quotas.” But he has also refused to shut down all affirmative action.

In December, the court heard Fisher vs. University of Texas for a second time to decide whether the school’s admission policy is constitutional.

Union fees

The court could deal a severe blow to the union movement in a case from California. The justices will hear a free-speech challenge to pro-union laws in more than 20 states that require all public employees pay a “fair share fee” to their union, even if they are opposed to the union and refuse to join.

Rebecca Friedrichs, an Orange County teacher, sued the California Teachers Association, alleging the forced fees violate her rights under the First Amendment. Friedrichs vs. CTA will be argued Jan. 11.

Voting districts

Voters elect representatives to Congress, state legislatures and city councils in districts that are drawn to represent equal numbers of people. But that could change.

The court is considering an appeal from Texas that argues these districts should represent roughly equal numbers of eligible voters, rather than using the current system, which counts all people, including children, immigrants and prisoners.

The appeal relies on the “one person, one vote” rule established in the 1960s. If the justices agree in the case of Evenwel vs. Abbott, the ruling could have a major effect in states such as California, Florida, New York and Illinois because they have large populations of immigrants.

Contraceptives

The court will decide its fourth case on Obama’s healthcare law, and the second involving a religious-freedom challenge to a regulation that requires employers to include no-cost coverage for contraceptives in their health insurance policies.

Churches are exempt from this requirement. Under a separate accommodation, religious nonprofits, such as Catholic charities or the University of Notre Dame, need not provide nor pay for the coverage, but they must notify the government of their religious objection.

In a series of lawsuits, Catholic bishops and Protestant colleges contend the accommodation did not go far enough. The Catholic leaders said they would be “complicit in sin” if they made the required notification because doing so would “trigger” a process for providing the disputed contraceptives.

Obama’s lawyers say the mere signing of a notification does not “substantially burden a person’s exercise of religion,” quoting the 1993 federal law on religious liberty. Nearly all of the U.S. appeals courts rejected the challenges, but the high court agreed to hear seven appeals from religious entities. They were consolidated into a single case, Zubik vs. Burwell, due to be heard in late March.

Immigration

The fate of Obama’s broadest effort to shield immigrants from deportation rests with the justices. His lawyers are appealing rulings by a judge in Texas and the 5th Circuit Court in New Orleans, which blocked Obama’s latest immigration action from taking effect.

It would have shielded as many as 5 million immigrants who have lived in the country illegally for at least five years and have a child who is a citizen or legal resident. Those who come forward and qualify would be offered work permits.

If the justices agree in the next few weeks to hear the case of United States vs. Texas, it will be a major test of the president’s power to change immigration policy without seeking approval from Congress. But if the justices turn down the appeal, Obama’s action will likely remain on hold until he leaves office.