What type of veto cannot be overridden by Congress due to the absence of action from the president?

The pocket veto is a specific type of veto that occurs when the president takes no action on a bill within a certain timeframe, typically ten days, while Congress is adjourned. Because Congress is not in session to receive the bill and potentially override the veto, the pocket veto cannot be countered. This means that the bill effectively dies without the president's explicit rejection or approval.

In contrast to the pocket veto, a regular veto involves the president actively rejecting a bill, which Congress can attempt to override with a two-thirds majority vote in both chambers. The line item veto, although it has been discussed, is not currently available to the president—having been declared unconstitutional by the Supreme Court. An executive veto is generally not a recognized term in the context of presidential power, as it does not correspond to any established type of veto used in legislation.

Therefore, the pocket veto is unique in that it effectively allows the president to prevent a bill from becoming law without the possibility of direct congressional override.