Sen. Chuck Grassley, R-Iowa, said Wednesday he had been "naive" about former President Joe Biden and argued Biden would not be remembered as an effective president.Grassley, who has served alongside nine presidents, told Miranda Devine on the "Pod Force One" podcast that he got along with Biden when they were both senators, noting they worked on legislation together and knew each other personally."I think its, if you feel like you know somebody well, its hard to believe some of the things that you originally heard, now you kind of know. I was a little naive about how I looked at the President Biden compared to Sen. Biden," Grassley said.Devine asked Grassley how he would assess Bidens time in office.TRUMP TELLS GRASSLEY TO TELL DEMOCRATS 'GO TO HELL' OVER BLOCKED JUDICIAL NOMINEES IN SENATE"Well, considering the fact that he doesnt look like he was running it at least in (the) recent two or three years I think hell never go down in history as a very effective senator or a very effective president," he said.Grassley told Devine he only had one face-to-face meeting with Biden after Biden became president. Grassley also acknowledged he didn't have "anything to judge it by" but said he felt a lot changed for the former president physically and mentally, pointing to what others have said, as well as seeing Biden on TV.Asked by Devine whether he thought Biden was being controlled by his staff, Grassley replied, "Yes.""When you do a thousand commutations and pardons, and you dont pay any attention to it, you arent doing your job," the Republican senator said.The podcast host also pressed Grassley on Bidens decision to pardon his son, Hunter Biden.Hunter was found guilty of three felony gun offenses and was also charged with federal tax crimes regarding the failure to pay at least $1.4 million in taxes.GOP SAYS DEMS ADMIT GUILT IN BIDEN HEALTH COVER-UP BY BOYCOTTING SENATE HEARING ON CONSTITUTIONAL SCANDAL"Im not surprised, but it shouldnt have been done, and it proves the guilt of Hunter Biden," Grassley responded.The senator reacted on X in December when Biden announced the pardon."Im shocked Pres Biden pardoned his son Hunter [because] he said many many times he wouldnt & I believed him," Grassley wrote. "Shame on me."Biden's office did not immediately return a request for comment.Grassley has made headlines recently for defending the Senates "blue slip" tradition, which drew criticism from President Donald Trump.CLICK HERE FOR MORE COVERAGE OF MEDIA AND CULTUREThe "blue slip" tradition in the Senate effectively gives Senate Republicans and Democrats the ability to veto district court and U.S. attorney nominees in their home states."Were also going to be filing a lawsuit on blue slipping," Trump told reporters in the Oval Office on Monday. "You know, blue slips make it impossible for me, as president, to appoint a judge or a U.S. attorney because they have a gentlemans agreement."Nothing memorialized. Its a gentlemans agreement thats about 100 years old, where if you have a president, like a Republican, and if you have a Democrat senator, that senator can stop you from appointing a judge or a U.S. attorney, in particular, those two."