WATCH: Republican senator refuses to say whether GOP will endorse Trump for re-election

Sen. Susan Collins (R-ME) said "it's too difficult to say" whether President Donald Trump would be endorsed by his own party for re-election in three years.

The Maine Republican told MSNBC's Hallie Jackson that she was disappointed by Trump's moral equivocation after a white supremacist march in Charlottesville resulted in the death of a counter-protester.

"The president had an obligation, a moral obligation, to speak with absolute clarity from the very beginning and stick with that, not shift back and forth, to denounce the neo-Nazis, the white supremacists, the anti-Semitism that we heard, and unfortunately he wavered back and forth," Collins said. "There are no good neo-Nazis."

Collins said the president failed to meet the expected standard of leadership.

"There should be no place for hatred, bigotry and racism in this country, and he should have said that very clearly," she said. "He did at times, but then he wavered back and forth."

Collins said she had not supported Trump during last year's campaign and had instead written in the name of House Speaker Paul Ryan, and she refused to say whether the GOP would back him for re-election.

"Too hard to tell, there is a long ways to tell between now and that point," Collins said. "It's too difficult to say."