Dear David Brooks, Better to use polling averages rather than cherrypick individual polls. Best, Retiring Guy

How Trump Wins Again by David Brooks. (The New York Times, 2/6/2020)

First of all, Speaker Pelois formally announced an impeachment inquiry on September 24, 2019.

Source: Key Dates in the Impeachment Inquiry Into President Trump

(The New York Times, 2/5/2020) 

Secondly, Trump's average approval rating has hardly budged since September 24, 2019.

Source:  Real Clear Politics (red arrow added)