He has advised numerous international bodies in the areas of human rights, war crimes and genocide, nuclear policy, and bio-warfare.

He stated that Amnesty, along with other human rights organisations in the US, failed to sufficiently criticise the Sabra and Shatila Massacre in Lebanon.

[7] Boyle added that Amnesty International was instrumental in publicizing the "Iraqi soldiers dumping children from incubators in Kuwait" hoax.

[8] He claimed aspects of organizational continuity and survival came ahead of human rights aims in Amnesty International.

"[7] During the war for independence of Bosnia and Herzegovina, Boyle became the first international-law legal adviser to the first Bosnia-Herzegovinian president, Alija Izetbegovic.

[11] In October 1992, Boyle participated in the International Tribunal of Indigenous Peoples and Oppressed Nationalities in the United States of America that convened in San Francisco.

Boyle, acting as a "special prosecutor", petitioned the tribunal to issue the following: In the conclusion of a 37-point legal brief, Boyle wrote that the United States federal government was a hostis humani generis, and called on the tribunal to "condemn and repudiate" it and "its grotesque vision of a New World Order that is constructed upon warfare, bloodshed, violence, criminality, genocide, racism, colonialism, apartheid, massive violations of fundamental human rights, and the denial of the international legal right of self-determination" for indigenous peoples.

In a three-hour speech entitled "The Restoration of Hawaii's Independence", Boyle claimed that the United States has conceded it unlawfully occupied the Kingdom of Hawaii and that fact alone "gives the Kanaka Maoli (Native Hawaiians) the entitlement to restore their independent status as a sovereign nation state.

Boyle added that Hawaiian independence groups will "have to wait until the Kingdom of Hawaii has achieved substantial diplomatic recognition and then I could file something in the international court of justice."

Boyle further stated that "Native Hawaiians operate in accordance with the Aloha spirit, which is similar to Mahatma Gandhi's Satyagraha force, and I take the position that if Gandhi can throw the mighty British Empire out of India with Satyagraha, Native Hawaiians can throw the mighty American empire out of Hawaii with Aloha."

Instead, Professor Boyle called on Clinton to be impeached for the "right reasons"—specifically: launching military attacks against Sudan, Afghanistan, and Iraq in violation of the War Powers Resolution and the U.S.

[17] In November 2011, Boyle was involved as a prosecutor in the four-day Kuala Lumpur War Crimes Tribunal in Malaysia, an organisation established by former Malaysian prime minister Mahathir Mohamad, an opponent of the Iraq War, to decide if President George W. Bush had violated international law.

[19] In April 2018, Boyle gave a statement regarding Trump's missile strike in Syria, asserting that it was a violation of multiple charters and legal statutes, a crime against peace, and an illegal and impeachable offense.

On September 13, 2001, two days after 9/11, Boyle appeared on The O'Reilly Factor to debate the legality of military action against Osama bin Laden and Afghanistan.

He warned against rushing into war without evidence, recalling that "58,000 men of my generation were killed in Vietnam because of irresponsible behavior."

"[30] Following the Gaza War, he advised Palestinian Authority President Mahmoud Abbas to file a declaration under Article 12, Paragraph 3 of the Rome Statute, requesting the prosecution of Israeli officials.

"[31][32] In an article published by the Atlantic Free Press, in October 2010, Boyle suggested that Israel change its name to "Jewistan – The State of the Jews", claiming: In fact, Israel has never been anything but a Bantustan for Jews set up in the Middle East by the White racist and genocidal Western colonial imperial powers in order to serve as their racist attack dog and genocidal enforcer against the Arab and Muslim world.

So Israel might as well finally change its name today to Jewistan, own up to its racist birthright, and make it official for the rest of the world to acknowledge.

[33]He concluded the article by stating: "In the meantime, the Palestinians should sign nothing with Jewistan/Israel and let this Bantustan for Jews collapse of its own racist and genocidal weight.

"[33] In May 2008, Boyle offered to "represent Iran in an international tribunal for trying Israel on charges of genocide of Palestinians", and reportedly demanded that his proposal be submitted to Ayatollah Seyyed Ali Khamenei and President Mahmoud Ahmadinejad.