GEOFF BENNETT: Welcome to the "News Hour."

With less than a year until the 2026 midterm elections, it's already expected to be one of the most expensive campaigns in history.

And how that money is being spent could be changing.

AMNA NAWAZ: At the Supreme Court today, major arguments that could reshape campaign finance laws.

Our Lisa Desjardins has more on the Republican push to remove key spending limits.

LISA DESJARDINS: The ads have begun.

The 2026 battle for Congress and a waterfall of spending are under way.

NARRATOR: North Carolina doesn't need another career politician.

NARRATOR: Jon Husted supported the tariffs that are jacking up prices.

NARRATOR: Life in Maine, the way it should be, is harder thanks to Janet Mills.

LISA DESJARDINS: And all of that could be significantly affected by the nation's highest court.

The case filed in 2022 by the Republican House and Senate campaign committees, as well as then-Senate candidate J.D.

Vance, sues the Federal Election Commission over current law.

That law puts a $7,000 limit on how much individuals can give a candidate per cycle.

But individuals can donate more than a million dollars to political parties.

So the law separates the two.

Parties are limited in how much they can spend directly with the candidates.

Those are called coordinated expenses.

Republicans want to remove those limits and be able to send more money to candidates.

Doing so would change decades of campaign law.

ADAV NOTI, Campaign Legal Center: So, all of these limits, all of these rules, they're all about preventing corruption.

LISA DESJARDINS: Adav Noti is the exec director of the Campaign Legal Center and a former lawyer at the FEC.

He says these limits were put in place after the Nixon Watergate scandal, which exposed large secret donations.

ADAV NOTI: There was a widespread bipartisan understanding that, while some amount of money is needed to run elections and campaigns, it is best if that be limited, that no undue amount of it come from any one source, and then it be fully disclosed to the public.

LISA DESJARDINS: This century, the Supreme Court has overturned some limits, including in the Citizens United case, removing caps for donating to super PACs and ruling they violated free speech.

That argument is central today.

CARRIE SEVERINO, President, Judicial Crisis Network: If you're telling someone they can't pay any money to help broadcast their speech, that's the same thing as limiting their speech.

LISA DESJARDINS: Carrie Severino is president of JCN, a conservative legal group which supports removing these limits.

She also argues the limits create a convoluted system, parties and candidates with the same goals, but which can't work together.

CARRIE SEVERINO: We want Americans to have information about their candidates.

And forcing that information to be incredibly costly by having all of these extra limits and tying the hands of the political parties who are trying to communicate with voters isn't a good way to do that.

LISA DESJARDINS: But Democrats see other motives.

MARC ELIAS, Founder, Democracy Docket: It's just that the Republican Party doesn't believe in campaign finance reform and they don't want these particular limits in place.

LISA DESJARDINS: Marc Elias is an elections attorney representing the Democratic Party before the Supreme Court.

He sees corruption risk.

MARC ELIAS: If the coordinated party's spending limits go away, then now the money that is going into those committees in these hundreds of thousands of dollar checks or million-dollar checks can now be spent on an unlimited basis to benefit a particular candidate.

And that opens up a risk of quid pro quo corruption, bribery.

That is exactly why the Supreme Court has upheld these kinds of base limits before.

LISA DESJARDINS: In today's arguments, Justice Brett Kavanaugh questioned how the court should balance concerns about corruption versus political speech.

BRETT KAVANAUGH, U.S.

Supreme Court Associate Justice: The combination of campaign finance laws and this court's decisions over the years have together reduced the power of political parties as compared to outside groups, with negative effects on our constitutional democracy.

I'm also concerned, of course, about quid pro quo corruption and the circumvention concerns.

LISA DESJARDINS: Justice Sonia Sotomayor and the court's liberal justices questioned if the case would lead to a steep slippery slope.

SONIA SOTOMAYOR, U.S.

Supreme Court Associate Justice: Once we take off this coordinated expenditure limits, then what's left?

What's left is nothing, no control whatsoever.

LISA DESJARDINS: Justices will issue a decision in the case by next summer.

For the "PBS News Hour," I'm Lisa Desjardins.