Yes. I just put this in before 1900 because that was when Liberia was founded.
First, some OTL info. Convinced that black people should have a permanent homeland in Africa, Marcus Garvey Jnr sought to develop Liberia- he launched the Liberia Program in 1920, along with plans to build colleges, industrial plants and factories "to manufacture every marketable commodity", and railroads as part of an industrial base from which to operate. Although his UNIA (Universal Negro Improvement Association) wasn't solely a "Back to Africa" movement, the organization did work to arrange for migration for African Americans who wanted to go there. In late 1923, an official UNIA delegation which included Henrietta Vinton Davis, Milton Van Lowe and Robert Lincoln Poston, travelled to Liberia to survey potential land sites. They also assessed the general condition of the country, from the standpoint of UNIA members interested in living in Africa. By 1924, the Chief Justice J. J. Dossen of Liberia wrote to the UNIA conveying the government's support: "The President directs me to say in reply to your letter of June 8 setting forth the objects and purposes of the Universal Negro Improvement Association, that the Government of Liberia, appreciating as they do the aims of your organization as outlined by you, have no hesitancy in assuring you that they will afford the Association every facility legally possible in effectuating in Liberia its industrial, agricultural and business projects."
By this stage, Garvey had already been sentenced to five years in prison for alleged "business fraud" in the running of the Black Star Line (considered one of J. Edgar Hoover's first successes, coming as it did after a memorandum from the then special assistant's office stating that "Unfortunately, however, he [Garvey] has not as yet violated any federal law whereby he could be proceeded against on the grounds of being an undesirable alien, from the point of view of deportation"). And in 1924, the Liberia Program was derailed, when the Liberian President unexpectedly ordered all Liberian ports to refuse entry to any member of the "Garvey Movement". This action closely followed the Firestone Rubber Company's agreement with Liberia for a 99-year lease of one million acres (4,000 km²) of land, assisted and subsidised by the American and European governments, at a price of 6 cents per acre, upon which to create the world's largest rubber plantation. Only two months earlier, Liberia had signed a deal to lease the same amount of land to the UNIA instead, at an unprecedented price of a dollar an acre ($247/km²). Upon his release in November 1927, Garvey was deported, and never allowed to return to the USA.
Firestone also provided a $5 million loan, quoted at a 7% interest rate, to the Liberian government to pay off its foreign debts, and to build the harbor needed by Firestone to export rubber from the plantation. However, this loan was given in exchange for complete authority over the government's revenues, which the Firestone Rubber Company would hold until the loan was totally repaid. The loan took a larger and larger portion of the Liberian government's incomes: it grew from 20% of the total revenue of Liberia in 1929, to 32% in 1930, to 54.9% in 1931, and nearly the whole national revenue of Liberia in 1932. An estimation made by a member of the American Legation in Liberia said that Liberia really paid a 17% interest rate for the loan, and Liberia only finally managed to repay the loans to the company (and wrest control of its own national revenues back from the Firestone Rubber Company) in 1952. And during the Great Depression, as rubber prices fell, Firestone stopped its development of the plantation, using just 50,000 acres in the end. By cutting wages in half, he deprived the Liberian government of tax incomes, and forced the government to miss a loan payment to the company in 1933. With his self-contrived cassus-belli, Firestone subsequently asked the US government to send a warship to Monrovia to enforce the debt payment, but President Franklin Delano Roosevelt rejected the "gunboat diplomacy".
Meanwhile, while imprisoned, Garvey had corresponded with segregationist Earnest Sevier Cox who was lobbying for legislation to "repatriate" African Americans to Africa. Garvey's philosophy of Black racial self-reliance could be combined with Cox's White Nationalism – at least in sharing the common goal of an African Homeland. Cox dedicated his short pamphlet
"Let My People Go" to Garvey, and Garvey in return advertised Cox' book "
White America" in UNIA publications. And in 1937, Garvey openly collaborated with the United States Senator from Mississippi, Theodore Bilbo, and Earnest Sevier Cox, in the promotion of a repatriation scheme introduced in the US Congress as the Greater Liberia Act. Bilbo, who was an outspoken supporter of segregation and white supremacy, and attracted by the ideas of black separatists like Garvey, proposed an amendment to the federal work-relief bill on 6 June 1938, to deport 12 million black Americans to Liberia at federal expense to relieve unemployment. He took the time to write a book entitled
Take Your Choice, Separation or Mongrelization, advocating the idea. Garvey praised him in return, saying that Bilbo had "done wonderfully well for the Negro".
So then, what if the gunboat diplomacy had gone ahead earlier; and with the Liberian government having defaulted on its unpayable debts and having already effectively ceased to govern itself, Liberia were subsequently forced to secede its sovereignty to the USA? This provokes widespread outrage and civil unrest among the black community in America, and instead of leaving Jamaica for London in 1935, in the aftermath of this event, Garvey travels to either Liberia or neighbouring Sierra Leone ITTL- the UNIA has a resurgence, multiple successors to the Black Star Line are established to repatriate African Americans to Liberia with their headquarters in Monrovia (a subtle hint to Liberia's fate IOTL, where 70% of the Liberian economy comes from the number of vessels registered under its flag), and when Senator Bilbo presents the Greater Liberia Act in front of Congress in 1938, his proposed amendment to the federal work-relief bill is taken seriously, and a slightly toned-down version of the Greater Liberia Act is implemented.
An African American 'Trail of Tears' subsequently follows, with numbers which eclipse those of the forced removals of the Native American tribes to Oklahoma a century earlier; in the next few years, over a million African Americans are deported to Liberia, more than doubling the size of the Liberian population. WW2 soon puts pay to the state-sponsored federal repatriation scheme, but 'black flight' to Liberia continues, as Liberia's fledgling industrial base, output and young working population swiftly become critical to the Allies' war effort. During the war years, Liberia's economy mushrooms to surpass that of many US states, and becomes presented as a black utopia; support for pan-Africanism, then largely associated with communism, starts to become increasingly vocal, along with support for anti-colonial independence movements across the rest of Africa, and the establishment of a Pan-African Socialist State. Post-war though, as the Iron Curtain falls, the USA decides that it can't afford to let the now profitable territory of Liberia become independent for strategic reasons, fearing that its most left-wing territory would subsequently go red and that it could take most of the rest of Africa with it. And as such, Liberia is soon inaugurated as a fully-fledged state of the USA.