The impeachment dam has broken.

More than half of House Democrats say they would vote to launch impeachment proceedings against President Donald Trump, a crucial threshold that backers said will require Speaker Nancy Pelosi to reconsider her steadfast opposition.

Though Pelosi has given no indication that even a significant majority of House Democrats embracing impeachment proceedings would shift her view, supporters of an inquiry argue that crossing the halfway mark among the caucus is a symbolic boost that could shift the political dynamic.