The Justice Department on Wednesday undercut efforts to revive the dormant Equal Rights Amendment, finding that an expired pair of deadlines imposed by Congress on ratification of the measure means it's too late for additional states to ratify it now.

Conservatives hailed the DOJ's move as a major victory, saying the ERA is a threat to their stances on abortion and transgender rights. The amendment, which would require ratification by three-fourths of the 50 states, holds that "equality of rights under the law shall not be denied or abridged by the United States or by any state on account of sex."

However, the amendment's seemingly innocuous text would create a slew of new legal problems, some activists said, and could be used as a kind of backdoor to legally enshrine abortion rights into the Constitution.

“Finally, we are hearing reason on this bad idea, now 100 years old, to force abortion into the Constitution, even as Roe v. Wade is falling apart,” said Students for Life of America President Kristan Hawkins. “Women did not have the kind of legal protections that exist today when this idea was first proposed; but times and the law has changed.”

COULD ROE V WADE BE OVERTURNED SOON?

Hawkins and SFLA argued that because the ERA prohibits distinctions based on "sex," it would negatively impact a host of laws that have benefited women, including the Equal Pay Act of 1963; the Civil Rights Act of 1964; the Equal Employment Opportunity Act of 1972; the Federal Minimum Wage Act of 1974, and the Pregnancy Nondiscrimination Act of 1964.

Progressives have argued for a definition of "women" that is subjective and based entirely upon individual self-identification, rather than objective characteristics like chromosomes or genitalia.

The DOJ memo by Assistant Attorney General Steven Engel comes as Virginia is poised to become the decisive 38th state to approve the ERA nearly four decades after Congress sent it to states in 1972, attaching a 1979 ratification deadline to it.

That deadline was later extended to 1982. During that time just 35 states ratified it — three short of the 38 needed.

“Because three-fourths of the state legislatures did not ratify before the deadline that Congress imposed, the Equal Rights Amendment has failed of adoption and is no longer pending before the States,” Engel wrote.

“Accordingly, even if one or more state legislatures were to ratify the proposed amendment, it would not become part of the Constitution,” he added.

WATCH: SOPHISTICATED POLITICAL AND LEGAL ANALYSIS FROM THE ONE AND ONLY ALYSSA MILANO

Engel's finding is unlikely to be the last word on the amendment.

Democratic Virginia Attorney General Mark Herring said Wednesday he's going to make sure the will of Virginians is carried out and the ERA is added to the Constitution

“Women in America deserve to have equality guaranteed in the Constitution," Herring said in a statement. “The fact that Republican attorneys general are suing to block the ERA, and that they now have the support of the Trump Administration, is absolutely repugnant.

FLASHBACK: WHY THE EQUAL RIGHTS AMENDMENT IS A FEMINIST DISASTER

On Tuesday, supporters of the ERA filed a federal lawsuit in Massachusetts aimed at clearing a legal path for adoption of the amendment.

The lawsuit argues that because the deadline was set forth in legislation authorizing states to ratify the amendment — and not in the three-sentence amendment itself — it's not constitutionally binding and Virginia's vote would put the amendment over the top.

“We are not surprised that the Trump administration acted swiftly to declare its opposition to the Equal Rights Amendment," said Wendy Murphy, a lawyer for Equal Means Equal, one of the groups that filed the lawsuit in Massachusetts. “This development makes our lawsuit even more urgent.”

CLICK HERE TO GET THE FOX NEWS APP

Engel also said Congress may not revive a proposed amendment after a ratification deadline has expired. He said the only option is for Congress to begin the process again.

Efforts by ERA opponents are underway to block its ultimate adoption as the Constitution's 28th Amendment, including a lawsuit filed in federal court in mid-December by Alabama, Louisiana and South Dakota.

Fox News' Bill Mears and The Associated Press contributed to this report.