The unexpected death of Justice Antonin Scalia comes less than a month before the Supreme Court hears its biggest abortion case in a decade.

On March 2, the Supreme Court will hear oral arguments in Whole Women's Health v. Hellerstadt, a challenge to a Texas law that has closed about half of the state's abortion clinics since 2013.

If the law is allowed to stand, abortion rights supporters say it would close all but about 10 of Texas's abortion clinics. Advocates on both sides of the abortion issue say this case could be the most important decision on abortion in 25 years.

Scalia has been a staunch opponent of abortion rights, and critical of the landmark Roe v. Wade decision in 1972, which established a constitutional right to abortion. "You want a right to abortion? There's nothing in the Constitution about that," Scalia said in a 2011 interview.

Scalia was a near-certain vote in favor of upholding the Texas law. Without him, things get a bit more complicated. But the key thing to know is this: Without Scalia, its very hard to see a world where the Supreme Court affirms the Texas law's constitutionality.

Here's why: There are almost certainly four votes against the law from the Court's liberal wing. And it's possible there are five votes, as justice Anthony Kennedy has been a swing vote on abortion cases. A 5-3 decision would be the best case for abortion rights supporters, as it would repeal the Texas law and prevent other states from passing similar restrictions.

The best case outcome for the abortion rights opponents, meanwhile, is a 4-4 tie. In that case, Supreme Court rules say that the decision of the circuit court is left in place without setting any constitutional precedent.

In that case, this would let the Texas law stand, since the Fifth Circuit Court of Appeals ruled in favor of the restriction. That would be far from an ideal outcome for the law's challengers and would leave abortion access greatly restricted in Texas.

But it also wouldn't give other states the clear signal that these types of restrictions are constitutional — something that abortion opponents would very much like to see.

Texas law would leave 900,000 women more than 150 miles from an abortion clinic

The case, Whole Woman's Health v. Hellerstedt, was brought by Texas abortion providers challenging Texas's House Bill 2, which the legislature enacted into law in July 2013.

That bill has two main restrictions, both of which the clinics challenge in this case. One was a requirement that all abortion clinics have admitting privileges at local hospitals. That piece of HB2 went into effect in September 2013, and forced 14 clinics that could not obtain admitting privileges to close.

HB2 also requires abortion clinics to become ambulatory surgical centers, essentially mini emergency rooms that can handle complex medical situations. Ambulatory surgical centers, for example, must have wide enough hallways to fit a gurney and larger operating rooms than abortion clinics typically use.

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Abortion clinics in Texas have said that upgrading to these new standards would cost upward of $1 million. They have argued that the new requirements are unnecessary, as abortions tend to have a very low complication risk. Approximately 0.05 percent of first-trimester abortions have complications that require hospital care.

Texas clinics have said because these upgrades are so costly, many facilities would close. Their lawyers previous stated that about 900,000 of Texas's 4.5 million reproductive-age women would live more than 150 miles from a clinic if HB2 stands.

The key legal question: Is the Texas law a substantial obstacle to abortion access?

The Supreme Court has, in previous rulings, articulated standards for judging the constitutionality of abortion restrictions like these. And one key standard the justices have settled on is whether a restriction places an "undue burden" on women seeking to terminate a pregnancy.

The Supreme Court has previously defined an undue burden as a law with the "purpose or effect of placing a substantial obstacle in the path of a woman seeking an abortion of a nonviable fetus." The Supreme Court has previously ruled that laws requiring women to notify their spouses of their abortion, for example, are an undue burden, as it could make it impossible for some women to access the procedure.

The Texas law requires abortion clinics to become mini emergency rooms

The Texas clinics argue that HB2 ought to fit the "undue burden" definition: Because it would force most Texas abortion clinics to close, it would become the type of "substantial obstacle" that the Supreme Court has previously found to be unconstitutional.

If the Texas law stands, the clinics argue, "every woman in Texas would have to live under a legal regime that fails to respect her equal citizenship status and would force her to grapple with unnecessary and substantial obstacles as a condition of exercising her protected liberty."

Texas: No evidence that women would be turned away from clinics

Texas has defended its new restrictions as not placing a substantial burden on those seeking abortions. As evidence, it points to the fact that the admitting privileges portion of the law has been in effect for more than a year, forcing 14 clinics to close. The clinics, they pointed out, presented no evidence of women who wanted to obtain an abortion not being able to do so.

The Fifth Circuit Court of Appeals used that argument to uphold the law in October.

"Demand for abortion services in Texas may decrease in the future, as it has done nationally over the past several years," the Fifth Circuit ruled. "The record lacks evidence that the previous closures ... have caused women to be turned away from clinics. Without any evidence ... plaintiffs do not appear to ... show that the ambulatory surgical center provision will result in insufficient clinic capacity."

The Fifth Circuit continued that "the evidence does not indicate, without specificity, that by requiring all abortion clinics to meet the standards of ambulatory surgical centers, the overall costs of accessing an abortion provider will likely increase."

Texas has also challenged the clinics' argument that the new restrictions are unnecessary because abortion is generally a safe procedure, saying it's not the place of the courts to second-guess the possible outcome of the law.

Abortion rights supporters have pointed to new research that suggests the state was wrong on this. According to the Texas Policy Evaluation Project, major Texas cities have seen significant increases in wait times at abortion clinics. In Dallas, where the average wait time for an abortion was five days prior to HB2, women may now wait as long as 20 days.