Also, today, more legal confusion over mail-in voting, with the first ballots for the upcoming midterm set to go out as early as next week.

This morning, more than two dozen Democratic-controlled states filed a new lawsuit against the U.S.

Postal Service challenging President Trump's executive order on mail-in voting.

The original case was deemed premature by the U.S.

Supreme Court earlier this week because the Postal Service rule had not been finalized.

That decision led a federal judge in a separate case today to lift a block on the president's order.

Legal challenges are likely to continue, but the USPS can for now continue with its final rule that says it can only deliver ballots to voters on an approved list of eligible voters.

President Trump is celebrating the primary wins of candidates he backed in South Carolina and Oklahoma.

That includes Darline Graham, the sister of the late Senator Lindsey Graham, who thanked the president for his support.

SEN.

DARLINE GRAHAM (R-SC): Our victory would not have been possible without you, and we are truly grateful.

(APPLAUSE) SEN.

DARLINE GRAHAM: South Carolina is truly Trump country.

GEOFF BENNETT: Graham, a political novice, was tapped to serve out the rest of her brother's term after he died last month.

She is seeking a full term of her own in November's election.

And, in Oklahoma, Mr.

Trump's preferred candidate, Tulsa businessman Mike Mazzei, narrowly won the Republican nomination for governor.

Turning now to the Middle East, Iran says it would bar all military vessels from passing through the Strait of Hormuz as part of a potential agreement with Oman to reopen the waterway.

The proposed agreement would last 30 to 60 days while the two countries work toward a permanent deal.

In a radio interview today, President Trump said the waterway has been cleared of mines and is -- quote -- "a very functioning strait."

But Iran's deputy foreign minister disputed the president's account.

KAZEM GHARIBABADI, Iranian Deputy Foreign Minister (through translator): If they have cleared the mines, then why aren't vessels passing through the strait?

This is nothing more than a claim.

Look, the Strait of Hormuz is unsafe for the passage of commercial vessels.

No one, other than the Islamic Republic of Iran, knows the locations of these mines precisely.

GEOFF BENNETT: Meantime, President Trump submitted a proposed nuclear agreement with Saudi Arabia for congressional review.

Under that agreement, the U.S.

would develop and support the country's nuclear program for 30 years.

But the president says Saudi Arabia must normalize relations with Israel before the deal can be finalized.

The FDA approved a landmark new drug today for pancreatic cancer that can extend survival times for patients with the disease, which is one of the deadliest forms of cancer.

The daily pill will be marketed under the brand name Rasonque.

It works by blocking a protein that fuels tumor growth.

Researchers found that it roughly doubled life expectancy when compared to chemotherapy from nearly seven months to more than 13 months and comes with fewer severe side effects.

Revolution Medicines, which makes the drug, says it'll have a sticker price of nearly $40,000 a month, but says much of that would be covered by insurance.

On Wall Street today, stocks ended a touch lower after some underwhelming U.S.

economic data.

The Dow Jones industrial average slipped about 100 points.

The Nasdaq fell about 20 points.

The S&P 500 ended virtually unchanged.

And star of stage and screen Tim Curry has died.

TIM CURRY, Actor: Come up to the lab and see what's on the slab.

I see you shiver with anticipation.

GEOFF BENNETT: The British-born actor rocketed to fame in the mid-'70s as a cross-dressing mad scientist in "The Rocky Horror Picture Show."

Curry had originated the iconic role of Dr.

Frank-N-Furter on London's West End before taking it to Broadway and then to the cult classic film.

With his sense of humor, expressive face and unmistakable voice, Curry brought a mischievous energy to roles in films like "Annie," Clue," and "Home Alone 2," among many others.

Curry suffered a stroke more than a decade ago that left him confined to a wheelchair, and he died yesterday at his home in Los Angeles.

Tim Curry was 80 years old.

Still to come on the "News Hour": the custody fight that's erupted after a surrogate refused to get an abortion; how first responders in one of the nation's hottest cities are fighting heat-related illnesses with bags of ice; high beef prices pressure the White House to reconsider its tariff policy; and country star Martina McBride remembers the legendary Dolly Parton.