The U.S. Supreme Court comes back from its winter break this week and plunges into a second half of the term as big as the first.

Between now and the end of arguments in April, the justices will hear cases involving the Trump Administration’s latest travel ban; the government’s ability to seize emails stored on foreign servers; fees paid by nonunion members to unions; another partisan gerrymander challenge, a racial gerrymander challenge, regulation of so-called pregnancy crisis clinics, and more.

Let’s take a moment to recap what the high court has already heard and is now awaiting decision. Between the start of the term in October and the end of the January argument cycle, six cases in particular (including a trio counted as one) raised issues for the justices with potentially huge ramifications for workers, elections, privacy, states’ rights and gay rights.

The justices could rule in any of these cases at any time.

The justices could rule in any of these cases at any time. Here are the issues they raise:

Do arbitration clauses in employment contracts that prohibit class or collective actions by workers violate federal labor law?

Was Wisconsin’s redistricting plan for state legislative districts an unconstitutional partisan gerrymander?

Does Ohio’s process for updating its voter registration rolls violate the National Voter Registration Act and the Help America Vote Act?

Does the Fourth Amendment prohibit the warrantless search and seizure of someone’s cell phone location data over the course of 127 days?

May Congress, consistent with the Constitution, prohibit states from authorizing sports-gambling schemes?

Does a Colorado anti-discrimination law violate the First Amendment speech and religion rights of a baker who refused, on religious grounds, to make a wedding cake for a same-sex couple?

These are difficult issues, and that may explain why the court has issued so few decisions so far this term — just four by the end of January. Chief Justice John Roberts Jr. strives for consensus, but sometimes it just won’t happen, especially on an ideologically divided court with a highly-charged docket.

Moving forward: The two-week February argument session, which begins Feb. 20, has three cases to watch closely.

On Feb. 26, the justices will hear arguments in Janus v. American Federation of State, County and Municipal Employees. They are asked to overrule a 41-year-old decision that has been reaffirmed many times. The decision upheld the constitutionality of so-called fair share fees paid by non-union members to public sector unions for their share of the costs of collective bargaining.

That old decision — Abood v. Detroit Board of Education — held that the fees had a minor impact on the First Amendment rights of non-union members and that impact was outweighed by employers’ interest in labor peace through bargaining with a single representative and the avoidance of “free riders.” But those fees, the court said, could not be used for political purposes.

Mark Janus is a child-support specialist at the Illinois Department of Healthcare and Family Services. He is not a member of the union and objects to the roughly $45 monthly fee he pays to the union that represents him. He argues that Abood was wrongly decided because there is no difference between bargaining with the government and lobbying the government—both are political speech.

Overturning Abood has long been a goal of the National Right to Work Foundation which brought the Janus case to the high court. In two decisions in 2012 and 2014, Justice Samuel Alito Jr. opened the door to reconsideration of Abood and then laid out a roadmap to overturning it.

The justices came close to overruling Abood in a different case in 2016. They deadlocked 4-4 after the death of Justice Antonin Scalia, who many believed would have been the fifth vote to overrule.

Chief Justice John Roberts Jr. strives for consensus, but sometimes it just won’t happen, especially on an ideologically divided court with a highly-charged docket.

More than 60 “friend of the court” briefs have been filed in the case. Conservative and libertarian legal organizations, among others, support overruling Abood, while labor unions, civil rights groups and others defend it. The Trump Administration is supporting Janus—a change in position from the Obama Administration which supported the union in 2016.

The second case being closely watched is United States v. Microsoft, to be argued a day later on Feb. 27. The government in 2013 served a warrant on Microsoft that sought emails from an alleged drug dealer that were stored on a server in Dublin, Ireland. The warrant was issued under the Stored Communications Act. Microsoft refused to give up the emails. The tech giant argued that the Stored Communications Act did not apply overseas.

At the heart of the case is the conflict between the government’s need for evidence to investigate and prosecute serious crimes, ranging from terrorism to fraud, and digital privacy. Microsoft warns that if the government can use a warrant to seize emails located outside the United States, foreign governments may act to seize emails inside the United States. It also sees the government’s action as a threat to the U.S. cloud-computing industry.

And finally, a good old-fashioned First Amendment challenge involving Minnesota’s law banning the wearing of political apparel—badges, pins, buttons, etc.—at the polls. In the 2010 election, the executive director of the Minnesota Voters Alliance wore a Tea Party shirt and a “Please I.D. Me” button to the polls. He was told he couldn’t vote unless he removed the apparel or covered them. He left and returned later to vote.

His organization and several individuals sued state government officials, arguing that the state ban violated the First Amendment. The case is Minnesota Voters Alliance v. Mansky.

This one should be fun, with lots of hypotheticals on what a voter can wear from our ever-creative justices on Feb. 28.