At what point should a President, especially in their first term running for re-election, stop being able to fulfill parts of their duties? Declaring war? Resp

At what point should a President, especially in their first term running for re-election, stop being able to fulfill parts of their duties? Declaring war? Responding to an attack? Talking to other world leaders? Advocating Congress to act on matters? Signing bills into laws? Naming post offices? Being allowed into the Oval Office? Independent of this specific situation, there has to be a line drawn somewhere. And that line is Inauguration Day. (A case could be made that some powers cease on Election Day for a lame duck President.)