When Balak sent for Bilam to come and curse the Bnei Israel, he says to him, I know: אֵת אֲשֶׁר תְּבָרֵךְ מְבֹרָךְ וַאֲשֶׁר תָּאֹר יוּאָר, “…whomever you bless is blessed and whomever you curse is accursed.” (Num. 22,6) Balak wanted Bilam to come and curse. Why did he add that he knows he can also bless?
Balak knew there are two ways he can defeat the Israelites. One way was that his armies would be strong enough to overcome the Bnei Israel with their might. If perhaps, his armies were not powerful enough to overpower them, he then wanted Bilam to curse them and weaken them to such an extent that Balak’s armies would be able to chase them away, even if he could not defeat them in battle.
That is why he emphasized that Bilam can also bless. Bless our armies to be able to defeat them. If that won’t work, then curse the Israelites so we can chase them away. Balak actually mentions both these possibilities in his message to Bilam. He said: אוּלַי אוּכַל נַכֶּה בּוֹ וַאֲגָרְשֶׁנּוּ מִן הָאָרֶץ, “…perhaps I will be able to destroy them and chase them away from the land.” (ibid)
Israel’s enemies today use the same approach. They tried to defeat Israel through wars and having failed they try by demonizing it.