WASHINGTON (Reuters) - A judicial activist advising U.S. President Donald Trump on potential nominees to the Supreme Court signaled on Sunday that two of the candidates would be a tougher sell to conservatives.

Leonard Leo said two names on the presidents short list to succeed retiring Justice Anthony Kennedy - Raymond Kethledge and Thomas Hardiman - had less-established conservative records, making it harder to line up support should they be selected.

I think in regards to Kethledge and Tom Hardiman they are a little less known by conservatives and their records are a little bit lighter so it might take some time, Leo told ABCs This Week on Sunday. Its important to have people who are extremely well known and have distinguished records.

Leo said, however, that Trump would ultimately succeed at lining up conservative support for anyone he selected.

Democrats see the seat being vacated by Kennedy, a conservative judge who sometimes sided with the courts liberal wing, as critical to maintaining abortion rights and key provisions of former Democratic President Barack Obama s healthcare plan.

Reuters reported last week that conservative federal appeals court judges Kethledge and Brett Kavanaugh were the two most serious contenders being considered by Trump for the Supreme Court, citing a source familiar with the process.