WASHINGTON (AP) — The Senate is poised to confirm President Donald Trump's nominee for education secretary by the narrowest possible margin, with Vice President Mike Pence expected to break a 50-50 tie.

The vote planned around 12 noon Tuesday will come after Democrats undertook a marathon speaking binge in the overnight hours in a show of opposition to the nominee, Betsy DeVos. DeVos is a wealthy GOP donor who has devoted herself to boosting alternatives to public education, sparking concerns among educators that she won't be a strong champion for the nation's public school systems.

Two GOP senators, Susan Collins of Maine and Lisa Murkowski of Alaska, have announced plans to oppose DeVos in a Senate split 52-48 between Republicans and Democrats.