Saruman Wasn't Wise At All. He Was A Blundering Fool
That was very obvious at the beginning when Gandalf ran to him "seeking his council" about the master ring and where it was. Gandalf totally took him into his confidence, but then Saruman broke it by revealing to Gandalf he was on Sauron's side.
If he kept Gandalf's trust, the Fellowship would have surely sought shelter at Isengard during their perilous quest to Morder and once Frodo was in his domain, Saruman could've taken the ring.
Saruman dug deep to create his huge Uruk-hai army, but he dug deeper into making himself more of a fool. He sent a band of Uruk-Hai out to get the ring from Frodo, but they got Merry and Pippin instead. The band never made it back to Isengard. They got slaughtered by the horse riders of Rohan.
Saruman also sent out 'Warg Riders' to kill the people of Rohan, but that was thwarted as well. The final blow came when his army of 10,000 descended upon Helm's Deep to start the process of killing all mankind, but that failed too.
The final blow came when he desecrated Fanghorn Forest by cutting down the trees there while creating his army. That riled up the ancient Ents who attacked Isengard and flooded it. He failed in every way possible, even when he lost, he still grasped at straws by taking over the Shire with his goons and turning the Hobbits into slaves. That didn't work either.
He failed at everything right from the beginning. Wise he might be, but in most other ways, he was not. He was a failure all through the ordeal.
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