Obama immigration plan in top US court
The Supreme Court appears to be divided over US President Barack Obama's plan to spare deportation for millions living in the country illegally.
Chief Justice John Roberts suggested in questioning he may side with Obama if the programmes enact some changes.
The White House wants to protect about four million people from deportation and give them work status in the US.
But 26 US states have objected, saying it will impose extra burdens like the issuing of driver licences.
President Obama announced the plan, known as Deferred Action for Parents of Americans and Lawful Permanent Residents (DAPA), in November 2014. The plan has been put on hold by lower courts.
The four liberal justices appeared to back Mr Obama's policies while the four conservatives, including Mr Roberts, appeared opposed or unsure.
There is a strong possibility the court will vote in a 4-4 deadlock, and block the programmes.
On the campaign trail on Monday in New York, Democratic front-runner Hillary Clinton said if she were to become president, she would "go further" than the Obama plan.
She said she will propose comprehensive immigration reform legislation within 100 days of being in office and create a path to citizenship for undocumented people.
The states opposed to the plan say it would increase costs for law enforcement, health care and education.
Republicans are unhappy that the president has - in their view - overstepped his powers by using executive orders that bypass Congress.
But Mr Obama says immigration reform has languished in Congress for too long.