By the terms of the Treaty, whereas Britain might intervene alone in Portugal in defence of its measures, France was specifically forbidden from doing so in Spain. After a combination of the Spanish army and British navy destroyed the absolutist forces of King Miguel and Don Carlos in the spring of 1834, Miguel fled but Carlos presented more of a problem, as he renewed his claim and raised more troops, joining forces with the Basques in their flight for independence. But neither Britain nor France was prepared for Guerrilla warfare so they therefore refused the Spanish Queen’s appeals for official military aid in 1835, sending token forces of volunteers or irregular troops instead. The recriminations between Britain and France was as a result from Palmerston’s reluctance to allow France the opportunity to restore her influence in Madrid by lending more effective aid to the liberal causes.
The friction that was being created by France’s and Britain’s involvement with the Spanish crisis was proving to be a threat to the Concert of Europe. As Britain and France were two of the major powers who were influential in the Concert and it decisions, it would be completely inappropriate to have disagreements and continuing conflict between these two powers when deciding on major issues. This would mean that the Concert would not come to unanimous decisions and there would always be disagreement, delaying the need to take action in delicate circumstances. This put the need for a strong decision accepted by all the powers in certain circumstances at risk as opposition between two powers could be destructive for the Concert.
The French Revolution of 1830 was also a threat to the Concert of Europe. The Revolution ended the rule of the Bourbon monarch Charles X., bringing power to Louis-Philippe. This change of regime had a significant impact on international relations for at least a decade. The outbreak of revolution was a threat because it alarmed the three eastern powers who renewed their pledges to sustain the 1815 treaties and even though they had made preparations for war, they had to accept the situation and merely warned France against any attempt to disturb the European status quo. The Concert feared that France’s revolution would influence revolts throughout Europe and therefore disturbing the balance of power which was their main aim. France was still regarded as the main danger in Europe, as it was feared that the new regime might wish to expand as the old revolutionary France had done. However, even though Metternich wanted to intervene, the other European powers would not agree to send troops to France causing frictions between the powers and fear of break up within or even Metternich taking the problem into his own hands.
The Belgian Revolt of 1830 was a result of the discontent with Dutch rule that arose in the late 1820’s, encouraged by French agents, and was mainly due to grievances over religion, taxation and the predominance of the Dutch language and Dutch officials. This revolt is also considered as a threat to the Concert of Europe as it directly challenged one of the arrangements made in the Treaty of Vienna to create a barrier against French expansion, so the appeal of the King of Holland for aid against rebellious groups would not be ignored. Belgium was part of Western Europe, whose political fate could not be determined by the Holy Alliance powers if Britain and France stood together. The powers feared intervention by the new ‘liberal’ French government in support of the Catholic Belgians, the eastern powers were horrified at this upset to the Vienna settlement and the effect that revolution was having generally.
The Polish revolt of 1830-1831 was another issue at the time which was creating problems for the Concert of Europe. The revolt began when the Tsar ordered a general mobilisation to deal with the potential revolutionary threat from France. In late November 1830 the Warsaw garrison, led by its junior officers, rose in revolt against Russian rule. The strength of the revolt lay in the backing of the Polish army which initially outnumbered the Russian forces, enabling the rebellion to win some early successes. In the late spring of 1831 the tide turned to Russian’s favour and in September Warsaw fell to the advancing Russian armies. Poland was then placed under military rule which abolished the Diet, the universities and the separate Polish army. A policy of Russification, including the use of the Russian language in schools, was vigorously applied to weaken Polish nationalism. Although the poles had assumed the western powers would come to their aid they were wrong, as with their aid they ignored the harsh realities of political life. Furthermore, the western powers could use their sea power to good effect to coerce the Sultan of Turkey and the King of Holland. This brought about friction with the powers as they had different views on how to react to the situation, and even though some wanted to help Poland out, such as Britain, as they did not want to challenge Russia and its right to rule over Poland which was founded on the treaties of 1815, one of whose objectives was to keep France in control.
The apparent division of the Great Powers after 1830 into two opposing ideological camps, the Liberal Alliance and the Holy Alliance, contained a potential threat to the working of the Concert of Europe. The success of the Concert depended, after all, on a degree of consensuses amongst the five Great Powers and a willingness to resolve problems of common concern by negotiation. But in the 1830’s and 1840’s a remarkable degree of flexibility developed in the alignment of the powers in some issues, despite their ideological differences, which contributed to the continuing strength of the Concert of Europe. Although these revolts and revolutions were seen as a threat to the Concert of Europe, if we are to analyse them, they were not a major issues as they never put the Concert in a situation of break-up or dysfunction. The Concert of Europe survived these tribulations and was in existence well into the 19th century, proving that these revolts did not pose a serious threat to its continuation.