Mark Deli Siljander (born June 11, 1951) is an American author and politician who served as a Republican U.S. Representative from the state of Michigan.

He criticized President Ronald Reagan's appointment of Sandra Day O'Connor to the Supreme Court, viewing her track record as insufficiently conservative.

[5] In Congress, Siljander's voting record was generally consistent with most other Republicans, although he became known for his firebrand conservative rhetoric; for example, he denounced "secular humanists" as having a "perverted" philosophy.

[7] On January 27, 1981, incumbent Congressman David Stockman resigned to serve as the director of the Office of Management and Budget in the Reagan administration.

[11][12][13] In 1981, Congress enacted an amendment, named after Representative Mark Siljander, to the FY1982 Foreign Assistance and Related Programs Appropriations Act specifying that no U.S. funds may be used to lobby for abortion.

[22] 1985 Siljander proposed legislation which would deny most favored nation status to countries that discriminate on cultural, ethnic or religious grounds.

[29] He also founded Trac5,[30] with the stated goal to implement faith-based diplomacy in real-world conflicts[31] Siljander's book, A Deadly Misunderstanding: A Congressman's Quest to Bridge the Muslim-Christian Divide was a 2009 Nautilus Silver Award Winner,[32] and has a foreword written by UN Secretary-General Ban Ki-moon, with whom Siljander worked closely to resolve the humanitarian disaster in Darfur.

"[34] Siljander was featured in the 2019 Netflix miniseries The Family, which details the history and activities of The Fellowship, a secretive Christian organization with ties to politicians and world leaders.

In the series, Siljander recounts his efforts to engage Muammar Gaddafi and help bring the Pan Am Flight 103 Lockerbie bombing terror suspects to justice.

[40] The group for which Siljander worked as an unregistered foreign agent was the Islamic American Relief Agency, a Columbus, Missouri-based Islamic charity with ties to terrorism, which hired Siljander in early 2004 to lobby to get IARA removed from a Senate Finance Committee list of charities suspected of funding international terrorism.

[41][42][43] IARA closed in October 2004 after it was added to the Treasury Department's list of global terrorist organizations due to the group's links to Osama bin Laden, al-Qaida and the Taliban.