I think Democrats threw this up as a Hail Mary. Polls divided this up into two categories: 1) Pro impeachment and No Removal and the other Pro Impeachment and Removal. At one time, I believe both were up in the 55%-60% range, which I think the Dems were using to gauge how they were gone move on this, but as time went by, support for either kept sliding further and further back to under 50%. The whole thing came off as rushed.
"Americans Still Divided on Impeachment, but Support Has Fallen Slightly
Americans remain split on whether to impeach and remove Trump from office, but the percentage who support these legislative actions has dipped slightly each time Gallup has polled on the matter since October.
Currently, 46% support impeachment and removal, down six percentage points from the first reading after House Speaker Nancy Pelosi announced the impeachment inquiry. Meanwhile, 51% oppose impeachment and removal -- up five percentage points over the same period."
Trump Approval Inches Up, While Support for Impeachment Dips