stylistic:tone
German troops

During the 18th century, states commonly hired foreign soldiers, including Britain. During the Seven Years' War, foreign soldiers comprised 10% of the British army and their use caused little debate. When it became clear additional troops were needed to suppress the revolt in America, it was decided to employ professional German soldiers. There were several reasons for this, including public sympathy for the Patriot cause, an historical reluctance to expand the British army and the time needed to recruit and train new regiments. An alternate source was readily available in the Holy Roman Empire, where many smaller states had a long tradition of renting their armies to the highest bidder. The most important was Hesse-Kassel, known as "the Mercenary State".

The first supply agreements were signed by the North administration in late 1775; over the next decade, more than 40,000 Germans fought in North America, Gibraltar, South Africa and India, of whom 30,000 served in the American War. Often generically referred to as "Hessians", they included men from many other states, including Hanover and Brunswick. Sir Henry Clinton recommended recruiting Russian troops whom he rated very highly, having seen them in action against the Ottomans; however, negotiations with Catherine the Great made little progress.

Unlike previous wars their use led to intense political debate in Britain, France, and even Germany, where Frederick the Great refused to provide passage through his territories for troops hired for the American war. In March 1776, the agreements were challenged in Parliament by Whigs who objected to "coercion" in general, and the use of foreign soldiers to subdue "British subjects". The debates were covered in detail by American newspapers, which reprinted key speeches and in May 1776 they received copies of the treaties themselves. Provided by British sympathizers, these were smuggled into North America from London by George Merchant, a recently released American prisoner.

The prospect of foreign German soldiers being used in the colonies bolstered support for independence, more so than taxation and other acts combined; the King was accused of declaring war on his own subjects, leading to the idea there were now two separate governments. By apparently showing Britain was determined to go to war, it made hopes of reconciliation seem naive and hopeless, while the employment of what was regarded as "foreign mercenaries" became one of the charges levelled against George III in the Declaration of Independence. The Hessian reputation within Germany for brutality also increased support for the Patriot cause among German American immigrants.

The presence of over 150,000 German Americans meant both sides felt the German soldiers might be persuaded to desert; one reason Clinton suggested employing Russians was that he felt they were less likely to defect. When the first German troops arrived on Staten Island in August 1776, Congress approved the printing of handbills, promising land and citizenship to any willing to join the Patriot cause. The British launched a counter-campaign claiming deserters could well be executed for meddling in a war that was not theirs. Desertion among the Germans occurred throughout the war, with the highest rate of desertion occurring during the time between the surrender at Yorktown and the Treaty of Paris. German regiments were central to the British war effort; of the estimated 30,000 sent to America, some 13,000 became casualties.