委托是一种民事法律行为，委托人授权代理人代表自己行使法律行为的能力和权限。根据法律规定，委托必须具备一定的要件才能有效成立。当委托不符合这些要件时，就会出现无效委托。

无效委托主要有以下三种情况：

一、委托人无民事行为能力

所谓民事行为能力，是指能独立进行民事法律行为的能力。根据民法典规定，未成年人、精神病人、醉酒者等无民事行为能力或限制民事行为能力的人不能成为委托人。如果他们进行委托，则该委托无效。

二、代理人无民事行为能力

同样，代理人也需要具备一定的民事行为能力才能有效接受委托。未成年人、精神病人、醉酒者等无民事行为能力或限制民事行为能力的人不能作为代理人。如果他们接受委托，则该委托无效。

三、委托事项违反法律或社会公共利益

委托事项必须合法且符合社会公共利益。如果委托事项违反法律或社会公德，则该委托无效。例如，委托代理人代为实施犯罪行为、委托代理人代表自己进行虚假诉讼等行为都是无效委托。

无效委托的法律后果

无效委托属于民事行为中的无效行为，不具有法律效力。无效委托产生的法律后果主要是：

• 委托关系不成立：无效委托不成立委托关系，代理人无权代表委托人行使法律行为。
• 代理行为无效：代理人在无效委托下进行的代理行为无效，不会产生任何法律后果。
• 委托人、代理人责任：如果无效委托导致第三人遭受损失，则无效委托人和代理人可能承担相应的民事赔偿责任。

避免无效委托的措施

为了避免无效委托，委托人应当：

• 确认自己的民事行为能力；
• 选择具有民事行为能力的代理人；
• 确保委托事项合法且符合社会公共利益；
• 签订书面委托书，明确委托事项和代理权限。

代理人也应当：

• 确认委托人具有民事行为能力；
• 审视委托事项的合法性和正当性；
• 了解自己的代理权限，避免超出范围；
• 谨慎行使代理权，维护委托人的合法权益。

INVALID AGENCY

Invalid agency refers to an agency relationship that does not meet the legal requirements for validity and therefore has no legal effect. There are three main circumstances that render an agency invalid:

1. Incapacity of the Principal

A principal must have legal capacity to enter into an agency relationship. This means that individuals who are minors, mentally ill, or intoxicated cannot validly act as principals. If they attempt to do so, the agency is void.

2. Incapacity of the Agent

Similarly, agents must also possess the legal capacity to accept an agency. Minors, mentally ill individuals, and intoxicated persons cannot act as valid agents. If they purport to do so, the agency is invalid.

3. Subject Matter Illegality

The subject matter of an agency must be legal and in accordance with public policy. If the purpose of the agency violates the law or morality, it is invalid. For example, an agency to commit a crime or to engage in fraudulent litigation is invalid.

Consequences of Invalid Agency

Invalid agency is a void act and has no legal effect. Consequently, the following legal consequences arise:

• No Agency Relationship Established: An invalid agency does not create an agency relationship, so the agent is not authorized to act on behalf of the principal.
• Invalid Agency Acts: Any acts performed by the agent under an invalid agency are void and do not bind the principal.
• Liability of Principal and Agent: If an invalid agency results in harm to a third party, both the principal (if the agency was ratified) and the agent may be held liable.

Preventing Invalid Agency

To avoid the pitfalls of invalid agency, principals should:

• Verify their own legal capacity;
• Select capable and qualified agents;
• Ensure that the subject matter of the agency is lawful;
• Draft a written power of attorney that clearly outlines the agent\'s authority.

Agents should also:

• Verify the principal\'s legal capacity;
• Scrutinize the legitimacy and legality of the subject matter;
• Understand their limited authority and refrain from exceeding it;
• Exercise their agency powers prudently to protect the principal\'s interests.