What does " make a dent with public opinion." (last line) mean?

Context>>>>>>>>>>>>>>>>>>
The Democrats have vowed to unleash new fronts in their investigations of Trump and heap pressure on the White House and Republicans to tackle gun legislation this fall in response to a new series of mass shootings.

On Friday, two House committees sent inquiries to the White House about administration officials' use of taxpayer money at Trump properties, after Vice President Mike Pence was forced to defend a stay at a Trump property in Ireland during an official trip there.

Congress is returning to do battle with a weakened Trump, who entered the August recess from a point of strength but has been battered by weeks of bruising headlines.

At the end of July, Trump was presiding over a strong economy and a political victory in the form of special counsel Robert Mueller's testimony to Congress, which largely failed to make a dent with public opinion.