The cartoon shows four main figures and depicts a wedding scene. The sole woman, the bride, is a heavy, unattractive woman with the words "foreign entanglements" written on her bridal gown. She represents Europe, which had just emerged from World War I.
The short preacher, who holds a prayer book called The League of Nations, represents the League, an international body that Woodrow Wilson believed would end further wars. The groom represents the United States.
The preacher asks if "any man" has cause to object to the marriage, showing that the couple is near the end of the marriage ceremony and just about to be wed. However, just at this moment, a fourth figure is crashing through a church window, representing the US Senate. He holds a scroll called Constitutional Rights, which is about to prevent the US from joining the League of Nations.
Because of the words "foreign entanglements" and the unattractiveness of the woman representing Europe, we can infer that the cartoon is celebrating the Senate's blocking of the "marriage" between the United States and Europe that the League of Nations represented. The US Congress did in fact block the US from joining the League, continuing a longstanding tradition of US isolationism that would not end until World War II.