Put it next to the one honoring Julius and Ethyl Rosenberg.
The usual vicious homosexual communist traitor.
God knows we have lots of them in the US.
We should build a memorial for Herbert Philbrick.
According to a Wikipedia article about Philby, his post-defection years in Russia were...well, less than glamorous. He took to drnking heavily and experienced many bouts of depression.
To that, I say “GOOD!”.
He was a true believer ‘til the end. If he had become disillusioned about Soviet-style Communism, the alcohol amazingly suppressed his urge to speak up. That and the fear that the few small perks he had could be taken away if he spoke up kept him silent.
For all the damage he caused, he can burn in hell for all I care.
A really detailed story of Philby and the Cambridge spies is yet to be written. It would be quite a challenge for a historian of the 20th century.
A maybe not quite a safe topic to research - even now.