Back in 1864, as he was looking for ways to finish off the rebellious South that wanted to stay with the original interpretation of the American Constitution, President Abraham Lincoln signed an act to encourage immigration:

Be it enacted by the Senate and House of Representatives of the United States of America in Congress assembled, That the President of the United States is hereby authorized, by and with the advice and consent of the Senate, to appoint a Commissioner of Immigration, who shall be subject to the direction of the Department of State, shall hold his office for four years, and shall receive a salary at the rate of $2,500 a year. The said Commissioner may employ not more than three clerks, of such grade as the Secretary of State shall designate, to be appointed by him, with the approval of the Secretary of State, and to hold their offices at his pleasure.

And what is the purpose of this act?

And be it further enacted; That no emigrant to the United States who shall arrive after the passage of this act shall be compulsively enrolled for military service during the existing insurrection, unless such emigrant shall voluntarily renounce under oath his allegiance to the country of his birth, and declare his intention to become a citizen of the United States.

Declare your intention to become a citizen and you can join the military. That is relevant because:

And be it further enacted, That all contracts that shall be made by emigrants to the United States in foreign countries, in conformity to regulations that may be established by the said Commissioner, whereby emigrants shall pledge the wages of their labor for a term not exceeding twelve months to repay the expenses of their emigration, shall be held to be valid in law

In your homeland, you can sign up for a one-year stint in the American military and have Uncle Sam pay to bring you over. Aha.

And be it further enacted, That there shall be established in the City of New-York an office to be known as the United States Emigrant Office; and there shall be appointed, by and with the advice and consent of the Senate, an officer for said City, to be known as Superintendent of Immigration, at an annual salary of two thousand dollars; and the said Superintendent may employ a clerk of the first class; and such Superintendent shall, under the direction of the Commissioner of Immigration, make contracts with the different railroads and transportation companies of the United States for transportation tickets, to be furnished to such immigrants, and to be paid for by them, and shall, under such rules as may be prescribed by the Commissioner of Immigration, protect such immigrants from imposition and fraud, and shall furnish them such information and facilities as will enable them to proceed in the cheapest and most expeditious manner to the place of their destination.

Government will help relocate them…

APPROVED, July 4,1864.

…and it goes into law on a symbolic date.

Lincoln was fighting a long war against the South, and he wanted to crush them permanently, and could think of no better method than importing an army, then settling it in the conquered lands, so that he could break up the ethnic populations there. As Plato predicted, importing foreigners was a method of staying in power and also, crushing the population and making them subservient.