The Supreme Court has been unusually busy in recent weeks redefining state election laws across the country, with justices poised again to weigh in on how voters cast their ballots ahead of next month’s mid-term elections.

The court so far has cut early voting by a week in Ohio, let North Carolina end same-day voter registration and blocked Wisconsin from implementing a new voter identification law.

Justices also are considering a challenge to Texas’ voter ID law.

In each ruling, the Supreme Court overturned lower court decisions that would have changed voting rules just weeks before the Nov. 4 elections. And while the high court typically doesn’t offer explanations when making such decisions, legal precedent has shown justices have a low tolerance for lower courts making changes to voting laws close to an election.

Here’s what the Supreme Court has done so far regarding state-level election laws:

Ohio

The Supreme Court late last month agreed to grant a request from Republican state officials to cut out a week in Ohio when people could register to vote and cast ballots.

Early voting in the key swing state was supposed to begin Sept. 30. But the court's order meant the start of early voting was pushed to Oct. 7.

Republican officials wanted to shrink the early voting window on the grounds it would help combat voter fraud and make elections less expensive. But a coalition of black churches and civil rights groups filed a lawsuit in an attempt to block the new rules.

A federal judge initially blocked the law. But the Supreme Court’s five conservative-leaning justices — Chief Justice John Roberts and Justices Samuel Alito, Anthony Kennedy, Antonin Scalia and Clarence Thomas — disagreed and voted to grant Ohio's request.

North Carolina

The Supreme Court last week overturned a lower court decision and allowed the state to end same-day registration during its early voting period.

The state passed a Republican-crafted law in 2013 ending same-day registration. An appeals court had ordered North Carolina to restart the practice until the state successfully petitioned the Supreme Court for an emergency stay.

Lawyers for the state argued that bringing back the provisions would cause voter confusion and trouble for local election officials to implement them again.

But the NAACP and other civil rights groups said that doing away with same-day voter registration was a voter-suppression tactic that would disproportionately hurt black and minority voters.

Wisconsin

The high court also last week blocked Wisconsin from implementing a law requiring voters to present photo IDs, overturning a lower court decision that would have put the mandate in place for the November election.

Wisconsin's photo ID law has been a political flashpoint since Republican legislators passed it in 2011. The GOP argues the mandate is a common-sense step toward reducing election fraud. Democrats insist that no widespread fraud exists and that the law is nothing more than an attempt to keep Democratic constituents who may lack ID, such as the poor, minorities and the elderly, from voting.

The law was in effect for the February 2012 primary but subsequent legal challenges put it on hold, and it hasn't been in place for any election since.

Meanwhile, the Supreme Court is considering a request filed Wednesday by civil rights groups and others to block a new Texas law requiring voters to show certain forms of identification in order to cast a ballot.

The move comes after U.S. District Judge Nelva Gonzales Ramos initially struck down the ID rule on the grounds that the Texas legislature enacted the law to purposely discriminate against minority voters.

But a federal appeals court on Tuesday blocked Gonzales’ ruling, meaning the measure would be in effect for the November elections if the Supreme Court does not intervene.

The high court may rule on the measure as early as Friday.

Wire services contributed to this report.