(Updates with more comment from the White House, Cardin)
NEW YORK/WASHINGTON, June 5 (Reuters) - U.S. President Donald Trump accused his own Justice Department on Monday of watering down his temporary travel ban on people from several predominantly Muslim countries, potentially hurting his case in the Supreme Court on the matter.
In a series of early morning Twitter messages, Trump returned to the issue of the travel ban that he raised immediately after an attack in London on Saturday night that killed 7 people and wounded 48.
Legal experts said Trump's tweets could complicate his legal team's defense of the ban, since they contradict some of the arguments the government's lawyers are making in court.
Trump has presented the measure, which seeks to halt entry to the United States for 90 days for people from Iran, Libya, Somalia, Sudan, Syria and Yemen and bar refugees for four months, as essential to prevent attacks in the United States.
Critics suing the government, including states and civil rights groups, say there is little national security justification for the move and the ban is discriminatory against Muslims. Federal courts have stopped it from being enforced.
"The Justice Dept. should have stayed with the original travel ban, not the watered down, politically correct version they submitted to S.C.," Trump tweeted, referring to the country's highest court.
"The Justice Dept. should ask for an expedited hearing of the watered down travel ban before the Supreme Court - & seek much tougher version!"
Federal courts struck down Trump's first temporary travel ban, an executive order he issued a week after taking office on Jan 20. To overcome the legal hurdles, he replaced it with a new order in March. The second ban was also put on hold by courts.
The Justice Department says the courts should look only at the text of the order, not at the president's comments during the 2016 election campaign about imposing a ban on Muslims.
"His tweets invite the question: if the second ban is 'politically correct,' what is un-P.C. about the original? And the answer is obvious: Trump told us its about banning Muslims," said Micah Schwartzman, a professor at the University of Virginia School of Law.
Trump, whose populist brand of politics includes criticizing political correctness as an evasion of uncomfortable truths, called in a statement on his campaign website for a "complete shutdown of Muslims entering the United States."
"The President's tweets may help encourage his base, but they can't help him in court," said Jonathan Adler, a professor at the Case Western Reserve University School of Law.
Trump's legal team asked the Supreme Court last week to reverse rulings by lower courts and allow the revised travel ban to go into effect immediately. At issue before the court is whether the travel curbs violate the U.S. Constitution's ban on favoring one religion over another.
The revised order removed language barring legal permanent residents and a clause that protected religious minorities. It also removed Iraq from the list of targeted countries.
Trump said in an interview with the Christian Broadcasting Network shortly after signing the first ban that it would help Syrian Christians fleeing the country's civil war, a comment lawyers challenging the ban have pointed to as a sign it meant to favor Christians over Muslims.
White House spokeswoman Sarah Sanders said Trump agreed to modify the language of the first order in an effort to satisfy the concerns of a federal appeals court that halted it, but he preferred the stronger action.
"He wants to go as far and as strong as possible under the Constitution to protect the people in this country," Sanders told a news briefing on Monday.
'SLOW AND POLITICAL'
Neal Katyal, an attorney for the state of Hawaii, which challenged the revised ban, said the president's comments only bolstered its case.
"It's kinda odd to have the defendant in Hawaii v Trump acting as our co-counsel. We don't need the help but will take it!" Katyal said in a tweeted response to Trump's posts on Monday.
Trump also tweeted on Monday that his administration was implementing tougher vetting of would-be visitors to the United States, adding: "The courts are slow and political!"
Legal experts said that comment could also undermine the government's case that the travel ban is urgently needed, given the government has said the temporary travel restrictions would free up resources to put in place tougher screening protocols.
Last week, the administration rolled out new policies on visa applications for some people who are deemed subject to greater scrutiny.
U.S. Senator Ben Cardin, who is the top Democrat on the Senate Foreign Relations Committee and opposes the ban, said on CNN the tweets showed the Republican president's disdain for the judicial branch.
Trump needs five votes from the nine-judge Supreme Court in his favor to put the ban into effect. With the confirmation of Trump's Supreme Court pick earlier this year, the court retains a 5-4 conservative majority, while the lower courts that have ruled thus far have been more liberal-leaning.
Peter Margulies, an immigration expert at Roger Williams University School of Law in Rhode Island, said of Trump's tweets, "To the extent that Trump is sort of a bull in a china shop, that might make the Supreme Court nervous."
On Friday, the Supreme Court asked the challengers of the travel ban to file responses to the emergency request by June 12. Trump's administration would then likely to file its own response before the court's nine justices make their decision.
White House senior adviser Kellyanne Conway defended Trump's tweets following the London attack. In an NBC interview on Monday, she cited a media "obsession with covering everything he says on Twitter and very little of what he does as president."
(Reporting by Mica Rosenberg in New York and Andrew Chung in Washington; Additional reporting by Lawrence Hurley, Susan Heavey and David Alexander; Editing by Bernadette Baum and Frances Kerry)