Jesus understood the meaning of the scribes asking this important question and indicated that John the Baptist was the second coming of Elijah. Jesus' own disciples could easily believe this, but the Israelites in general could not so easily believe it. John the Baptist did not come directly from heaven and he himself even denied he was Elijah (John 1:21). Jesus knew that the people would not easily accept this, saying, "If you willing to accept it, he is Elijah who is to come" (Matt. 11: 14).
Jesus said that John the Baptist was the Elijah whom the people had been long awaiting, but when John himself denied this, whom would the people of Israel believe? Naturally, it would depend on how these two were viewed by the people of that time.