Greetings! Your friend makes a rather curious argument, and I would also be interested in hearing what evidence they use to assert what is a fairly bold claim. Whilst the historical narratives of Anglo-American relations certainly does not point towards the US and UK being particularly close at the outbreak of the First World War in 1914, it certainly does not point towards the USA being against Great Britain. Parts of this response have been adapted from a previous one of mine regarding Anglo-American relations and the USA's decision to enter the war for geopolitical reasons, so feel free to read either of those as follow-up comments. Let's begin.

Anglo-American Relations

At the outbreak of the First World War on August 4th, 1914 - the date on which Great Britain declared war on the German Empire - the American government and public were content to remain neutral in the coming conflict. Now we must stress here, the USA was certainly not isolated from the events which would unfold in Europe in the coming years. The government under President Woodrow Wilson would keep abreast of the latest developments "across the pond", and American newspapers regularly updated the public about how the war was unfolding as well.

At the outbreak of war, the government saw no need to get involved with the hostilities for the "umbrella" motive that the US was not connected to Europe in such ways that necessitated her participation in the Great War. It did not, unlike Germany, France, or Russia, have any standing mutual defense pacts with the to-be combatant nations. It did not feel as though it was particularly connected with the ethnic tensions that had been plaguing the Balkans and the Austro-Hungarian Empire in the past few decades, and it had no obligation to come to the aid of a particular European country when it was invaded (as Britain claimed when it came to Belgium's "aid").

The American people as whole also saw no reason for their country to get involved with the war in Europe. Granted there were certainly minority voices at the outbreak of war and up until 1917 which were pro-Central Powers or pro-Entente, but America in 1914 was playing the role of "spectator", cheering on neither side until it became more and more apparent that there was a need to take sides in the war. The American public itself was divided into two sides with no clear majority up until 1917. On the one hand, America was full of ethnic German-Americans, whose vote Wilson may have wished to secure by promising neutrality in the coming years. There were also Irish voters in the Eastern cities, whose fury at the British oppression during the 1916 Easter Uprising meant they were against the US joining an old enemy. On the other hand, the Pro-British side was formed of the "Wasp" (White Anglo-Saxon Protestant, as Michael Howard terms it) supremacy on the east coast, as well as notable figures such as newspaper magnate William Randolph Hearst and ex-President Theodore Roosevelt. Neither side could claim the majority up until 1917, so America had to remain politically neutral in the whole affair.

For the purpose of focusing on OP's question, let us step back from this thread of narrative and zoom out to the wider question of how Anglo-American relations stood at the outbreak of war.

The Eagle and the Lion

It is often a common misconception that the US 'had more cultural ties' to the Entente powers (particularly Britain and France), and that these ties propelled her to join the war in 1917 on their side. At the outbreak of war, Wilson's government shared the view that British navalism was just as bad as German militarism, and this was a sentiment that many in America's public shared when the first shots were fired.

This view was nothing particularly new when one looks at the larger background and even from the British point of view. Although relations had certainly improved from the America Revolution, there was always an element of friction between the Old World maritime empire and the New World commercial star. Most prominently, the American government had clashed with its counterpart in London ("across the pond", to use an apt Britishism), over the Monroe Doctrine, and the belief that Washington possessed the rights to influence affairs in Latin and South America. In the Venezuelan crisis of 1895 with Britain over a border dispute in British Guiana, the American government under President Grover Cleveland attempted to intervene in the matter, but British Prime Minister Lord Salisbury was unwilling to entertain such demands. He famously took four months to reply to the American appeal for arbitration on the matter, and commented that Washington had "no apparent practical concern" in a dispute between a British possession and another state.

Added onto these territorial and influential concerns was the rise of American naval power, when President Theodore Roosevelt convinced Congress in 1907 to approve the funding of a Navy which was second only to Britain's. As John Darwin remarks, this proved another serious concern for the British government back in Whitehall, already dealing with a rising naval threat from the German Empire:

"But the most significant change, from the British point of view, was the new commitment to naval power in the presidency of Theodore Roosevelt (1901-9). By 1907, he had persuaded Congress to fund the building of a fleet second only to Britain's. For the embattled Royal Navy, a new sea challenge to its rear joined the new sea challenge to its front."

However, for all of these seemingly grave threats to British interests and continued imperial prosperity, America did not go on to become the major thorn in British foreign policy that Wilhelm II's Germany would be. This was in part due to Britain's own overtures: they renounced claims to the Isthmus of Panama in the Hay-Pauncefote Treaty of 1901, and Prime Minister Arthur Balfour (r. 1902-1905) announced that Britain was no enemy of the Monroe Doctrine. It was also however, due to the fact that within the United States, public opinion was not shifting decisively towards a "navalist" viewpoint (as possessed by Roosevelt and his successor, George Howard Taft). Congress reigned in the naval expansions shortly after Roosevelt's initial success, and they maintained a commitment to the Americas, not Europe.

Alongside these considerations, Washington also realised that the situation in the world was pushing them towards conciliation with the British. The Philippines no longer seemed like a military salient in Asia after the 1905 defeat of Russia at the hands of Japan (since 1902 an ally of Britain), and the onset of the Mexican Revolution in 1910 re-awakened American fears that European states would take advantage of the unrest to challenge the Monroe Doctrine once more. John Darwin on this most interesting development:

"As a result, the social and cultural rapprochement between Britain and America, and the appeal of 'Anglo-Saxonism' on both sides of the Atlantic, had its counterpart in diplomacy. If British leaders repudiated all thought of Anglo-American conflict, it was no more thinkable in Washington. British naval supremacy, remarked Theodore Roosevelt, was 'the great guaranty for the peace of the world.'...To American opinion, concludes a recent study, the real guarantor of its Atlantic security was British not American sea-power. On this calculation, the United States looked less like an imperial rival and more like a forceful, determined 'super-dominion'."

In other words, though America appeared to be a rising economic and political threat to the British Empire's security (or at the very least, a serious challenger to its Western Atlantic sphere), in reality the two governments shared the view that conflict with the other was not in their best interests; a "mutual understanding" of sorts that preceded the collaboration of the First World War (or to be pedantic, 1917 onwards).

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