"She would not get a majority either in the Judiciary Committee or the floor," said Schumer on NBC's "Meet the Press."
Schumer, who serves on the Senate Judiciary Committee, said he is concerned about Miers' legal qualifications, her judicial philosophy and her independence from President Bush.
He said Miers' confirmation hearings will be "make or break in a way they haven't been for any other nominee in recent memory."
Sen. Kay Bailey Hutchison, R-Texas, defended Miers and said the White House has no intention of withdrawing Miers' nomination.
"I think they have complete faith in her, as I do," said Hutchison. "She is totally qualified for the Supreme Court of the United States."