There are few distinctions in Congress as high as the one afforded the late Rev. Billy Graham at the U.S. Capitol Wednesday and Thursday. Graham will “lie in honor” in the Capitol Rotunda.

Note that Graham will “lie in honor,” not “in state.” We should refer to Graham as “lying in honor” rather than “lying in state.”

There is little which distinguishes someone from “lying in honor” rather that in “state.” Officially, “lying in honor” is one step below “lying in state.” The pomp and circumstance is much the same. But it formally is one level below “state.”

The Capitol Rotunda is considered to be the the most “holy” place in the American political experience. That’s why Congress reserves such ceremonies in the Rotunda for some of the country’s most-eminent citizens.

Most of those honored in the Rotunda have lain in state. Henry Clay was the first in 1852. In recent memory, others have included President John F. Kennedy, FBI Director J. Edgar Hoover, Sen. Hubert Humphrey, D-Minn., Sen. and Rep. Claude Pepper, D-Fla., President Ronald Reagan and President Gerald Ford.

Sen. Daniel Inouye, D-Hawaii, was the last to lie in state in December, 2012. Inouye represented Hawaii in either the House or Senate since it was admitted to the union until he died in 2012.

President Ford was the last President to lie in state in late December 2006 and January 2007.

There are no official rules to determine who lies in state or in honor. But both bodies of Congress must approve a resolution sanctioning usage of the Rotunda for such an event.

But “lying in honor” appears to be a more recent phenomenon. Graham is the fourth such person to lie in honor in the Capitol. The three others were U.S. Capitol Police Officers Jacob Chestnut and John Gibson and civil rights icon Rosa Parks.

Chestnut and Gibson were killed during a July 1998 shootout at the Capitol. Until 9/11 Chestnut and Gibson were the only persons killed defending the U.S. Capitol. The others who died were aboard Flight 93, the plane which was headed toward the Capitol on 9/11 and crashed near Shanksville, Pennsylvania. Parks lay in honor in 2005.

Graham will have a military and USCP honor guard unit on hand inside the Capitol.

Fox News is told that a flight carrying Graham’s body will land tomorrow morning at Dulles International Airport outside Washington and be escorted via motorcade to the Capitol. Fox News has learned the motorcade will come from the Dulles Toll Road to I-66 and then into D.C. across the Roosevelt Bridge and down

The hearse carrying Graham will arrive at the Capitol around 10:30 a.m. ET. Military guards will then lift Graham’s casket and carry it up the East Front Steps of the Capitol and into the Rotunda.

Once inside the Rotunda, Graham’s body will rest on an unsanded, pine platform called the “catafalque.” Workers at the Capitol constructed the catafalque to hold the coffin of President Lincoln in 1865. Officials have used the catafalque used ever since for formal funerals and memorials on Capitol Hill, including Graham’s service.

The Architect of the Capitol used to keep the catafalque in the tomb at the Capitol, two floors below the Rotunda floor. That’s the spot where George Washington was originally to be buried. But instead, Washington is interred at Mount Vernon. They moved the catafalque to the Capitol Visitor’s Center when it opened in 2008.

President Trump will travel to the Capitol tomorrow morning for the service and lay a wreath. Only family members, lawmakers and other dignitaries will be present in the Rotunda for the service tomorrow morning. Members of the public can file through the Capitol to pay their respects beginning at 1 p.m. ET through the evening.

The honor guard will stand watch over Graham’s casket throughout the night. They will then escort Graham’s casket out of the Rotunda on Thursday morning. The public will not be permitted in the Capitol for the Thursday departure.

The identities of some Americans who have laid in state are a mystery. That’s because Congress has held ceremonies for unknown soldiers from World War I, World War II, the Korean War and the Vietnam conflict to lie in state in the Rotunda,

It’s also notable for who hasn’t laid in state or honor in the Capitol. Most Presidents lie in state. But the family of President Richard Nixon surrendered that honor, thinking some people may not be respectful.

There was an initial plan for Sen. John Glenn, D-Ohio – the first American to orbit the Earth – to lay in state or honor in the Rotunda. Glenn first burst onto the public scene with his historic voyage in 1962, circling the globe three times. Glenn then retired from the Senate in 1999. But he lived until late 2016. Glenn’s plan evolved over time.

Senate Majority Leader Robert Byrd, D-W.Va., the longest serving senator in U.S. history, did not lie in state or honor in the Rotunda. Instead, Byrd laid in repose in the Senate chamber.

Sen. Ted Kennedy, D-Mass., had no formal services in the Capitol. However, the hearse bearing Kennedy’s casket drove across the Capitol plaza en route to his final resting place at Arlington National Cemetery in 2009.

A special Amtrak train carried the body of Sen. Frank Lautenberg, D-N.J., back to Washington after his death in 2013. Lautenberg lay in repose atop the catafalque in the Senate chamber before his burial at Arlington National Cemetery.