Your question is posed in very vague and general terms. Depending on the result of the lawyer's neglect, there could be a valid claim for malpractice. There would need to be provable financial losses.
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Based upon the few facts you presented, it is not possible to say whether there was any malpractice. The attorney generally knows better than the client when and whether to object and how to cross-examine. During trial, clients often wish to delve into details which the attorney determines are not critical to the case and could in some cases actually cause harm if addressed. Take a copy of your trial transcript, along with all papers, pertaining to your case and discuss your situation with an attorney who is experienced in bringing legal malpractice actions.