Ulster became associated with Unionism when all nine counties had Conservative seats, while the rest of Ireland had only two seats. This is how the Ulster Unionist party were formed, because Ulster was linked in with Unionism as a whole, which meant if Home Rule was to be introduced then Ireland would be run by the Irish Nationalist Party, who were very much opposed to Ulster and the Conservative Party who backed them.
The economic difference between Ulster and the Rest of Ireland was very obvious, as everywhere in Ireland was Agrarian, except for Ulster where there was a "truly industrial economy". As a result of this Ulster depended on the maintenance of links with Britain, in other words Ulster Unionists had a vested economic interest in preseverving the Union because Britain provided them with everything they needed to produce goods efficiently and at not too high a price, therefore if the Home Rule occured then the economy in Ulster would fail along with its political and religious aspects.
In 1906 when the Liberal party won power, The ulster Unionists had to increase pressure as well as their own party, because now the Liberals, who wanted to impose home rule, were in power they had more potential power themseleves. And although the Irish Question was seen as lesser problem now, it still meant the Ulster Unionists had to become stronger, as by 1910 it would eventually it was a main concern of the Liberals because the conservatives had gained an extra seat and they themsleves had lost two, so the conservatives had slighty more power in the house of Lords and therefore would push for Home Rule for Ireland, so the Liberals had to listen, as the parliament act stopped them from refusing to pass the bill again. And when the Parliament act became law in 1911 it meant that Ulster had to be extremely determined to fight Home Rule. The Ulster Unionists began preparing to resist the thrid Home Rule Bill as soon as the Parliament act became law, this resistance was lead by the leader of the Uniost Party, James Craig, and the the leader of the Ulster Unionist Council, Edward Carson. They needed to put pressure on the third home rule bill as the bill could not be rejected three times in the House of Lords, and therefore would become law if it was brought into parliament a third time. To create this pressure they organised mass meetings, urging Unionists to resist it. This culminated into the creation of the 'Covenant Day' (28th September 1912) on which people were asked to sign a covenant drawn up by Edward Carson. Signing this bill meant that the person signing it was commited to oppose Home Rule 'using all means which may be necessary'. It eventually amassed 250,000 signitures, with some people signing in their own blood. The is extremely strong view was backed by Bonar Law, who said they had a right to use arms to resist home rule and as the Conservatives had been out of power since 1906 and were rapidly gaining more power (January 1910 election) they had nothing to lose so they threw all the backing to the Ulster Unionists. They hoped this would gain them more popularity and therefore more power. Basically Bonar Law had said that the Liberals were bargaining with the Irish Nationalists over Home Rule, because they did not want any revolt in ireland which would in effect alter their power. This lead to the creation of the 'Ulster Volunteer Force' in january 1913, which consisted of Ex-British military officers, who, using force were going to fight for the abolition of Home Rule.
Carson wanted 'all or nothing' for Ulster and would not accept the compromise made by Asquith when he offered Ulster a six year exclusion from Home Rule. This showed grit from the Unionists and proved how they were not going to give up until Home Rule was abandoned, and this grit was sustained until and throughout the first world war.
Ulster was a completely different place when compared to Southern Ireland. It was religiously, politcally and economically different to the rest of Ireland, which made it seem as if it was not part of Ireland at all, and it did not want to be. It had to remain so determined to resist Home Rule because if it did not then it would not be able to carry on running as it was currently doing. The industry relied on Britain, and without Britains support it could not prosper. It was the only manily Protestant area of Ireland, as Southern Ireland was mainly Catholic, which meant if home rule became law the greater number of Catholics in Ireland (about 2 million more Catholics) would 'rule' over the protestants ("home rule means rome rule"). And as it was a Conservative/Unionist area it would be predominately run by the Irish Nationalist Party. All of these factors meant that the Ulster Unionists had to be determined to resist home rule, because if they laid down then it would bring about the downfall of not only the Unionsts, but the Conseravties and the whole of Ulster itself