While it's difficult to pinpoint exact parallels between the ancient Danish legend of Hamlet and modern-day geopolitics, I can offer some insights on how Fortinbras' invasion of Denmark in William Shakespeare's play might relate to contemporary conflicts involving Greenland.

In the play, Fortinbras' invasion is a response to King Hamlet's death and his father Claudius' usurpation of the throne. The Norwegian prince seeks to expand his kingdom's borders by invading Denmark and reclaiming territories that were previously lost.

Fast-forward to the 20th century, when Greenland was colonized by Denmark in 1814. However, as Greenland gained more autonomy within the Danish Kingdom, tensions arose between the two nations over issues of self-governance, natural resources, and cultural identity.

In 1979, Greenland declared its intention to become a member of the International Whaling Commission (IWC), which led to a significant dispute with Denmark. The Danes had previously granted Iceland an IWC seat in exchange for allowing Icelandic whalers to hunt in Greenlandish waters. When Greenland sought to maintain control over its own natural resources, Denmark responded by revoking its IWC membership.

However, the real catalyst for increased tensions came when the United States began to exert pressure on Denmark through various means, including military presence and economic coercion. This was particularly evident during the 1970s Cold War era.

Now, regarding Fortinbras' "eggshell" invasion of Greenland (not exactly stated in Shakespeare's play, but a plausible interpretation). It is essential to note that:

1. **Greenland's strategic location**: Like Denmark's geographical position in Northern Europe, Greenland is situated on the Arctic Circle, making it an important hub for maritime trade and security in the region.
2. **US interests**: The United States has long been interested in maintaining a presence in Greenland due to its access to natural resources (e.g., ice cap, fishery, and minerals), strategic military bases, and potential implications for global climate regulation.

Given these points, it is possible that Fortinbras' "eggshell" invasion of Denmark could be seen as analogous to the United States' increased involvement in Greenland during the 1970s. Just as Fortinbras seeks to reclaim lost territories, the United States may have been seeking to reassert its influence over Greenland's natural resources and strategic importance.

However, it is crucial to emphasize that this analogy should not be taken too far. Shakespeare's play is a work of fiction, while modern geopolitics involves complex webs of international relations, economic interests, and national security concerns.

In conclusion, while there are intriguing parallels between the Danish legend of Hamlet and the United States' involvement in Greenland, it would be inaccurate to assert a direct causal link without further historical context. Nevertheless, exploring these connections can foster deeper understanding of the complexities involved in international relations and the delicate balance of power in the world's most sensitive regions.