Federalism has become the latest fashionable trend in the UK’s constitutional debate, an easy middle-ground for politicians who want to reach out to unionists and nationalists alike, or to maintain a vaguely pro-UK stance while avoiding the charged label of “unionist”. It has become ubiquitous throughout all the mainstream unionist parties, and various models of federalism or quasi-federalism now dominate unionist discourse. The federalist proposals being put forward by the mainstream parties are so radical that they are barely recognisable as unionist at all, and this is because there is really only a paper wall between federalism and separation. If we consider the many stages of the devolution process that have led Scotland so far down the path to separation that it finds itself in today, federalism represents the last step before the abyss of outright separation. It has been termed ‘independence lite’ or ‘home rule’, and would indeed involve a constitutional arrangement that is far closer to independence for the four home nations than to any arrangement we have ever enjoyed in Union.
To offer a critique of federalism, some clarification should be given on what exactly is meant by the term. A federal UK would be one in which parliaments for the four constituent parts would each be largely responsible for governing their own domestic affairs. The UK Parliament would deal with mostly external matters like foreign relations and border control. Westminster would therefore not be insignificant, but it would cease to have any real impact on our everyday lives. Health, education, social spending, transport, economy, environment and all matters of everyday governance, as well as the vast majority of taxation would be the preserve of the largely autonomous parliaments for England, Scotland, Wales and Northern Ireland. Writing for The Telegraph, Philip Booth details it as thus:
“There should be a UK parliament that is responsible only for defence, border control, foreign policy and (if we keep central banks – I would prefer to see them scrapped) monetary policy and financial regulation. The UK government would also be responsible for the management of the existing national debt. The federal parliament should meet once a month and would probably be responsible for about 20 per cent of UK government spending (including debt interest)… Everything else should be the responsibility of a Scottish government.” 
For Scots, this would mean being governed almost entirely by an SNP-dominated parliament in Edinburgh and having next to no say on any domestic affairs at our national British Parliament. This is hardly what we voted for on September 18th 2014, nor could it be considered unionist in any meaningful way. It is the ‘home rule’ that the SNP demanded when they were originally formed back in 1934. Like the outright separation of the modern SNP, it involves a mass transfer of powers from Westminster to Holyrood, and a significantly looser, weaker form of union. It is a serious attack on the Union of 1707, which was primarily a parliamentary union that brought Scots and English together under a single UK Parliament.
These proposals must seem frightening to any unionist who wants something more than a nominal union. But federalism, or only slightly less drastic models of quasi-federalism, is now the dominant strain of unionist thought in the Labour, Liberal Democrat and Conservative parties. The Liberal Democrats have outlined plans for what they term ‘home rule’, with Scottish leader Willie Rennie stating that “home rule for Scotland could work well, but would be even better if it were part of a move towards a federal United Kingdom, where every part of the United Kingdom could have similar levels of responsibility.”  Prior to last year’s election, ex-Labour leader Ed Miliband promised a Home Rule Bill for Scotland if a Labour government was elected.  Jim Murphy joyously exclaimed that “Home rule is now a prize within our grasp” as the government went about delivering the notorious pre-referendum Vow, and handing over mass new powers to the Scottish Parliament. 
The home rule and quasi-federalism being delivered through the Vow is not enough for some leading Conservatives. Adam Tomkins, in reference to the Smith Commission which was formed to deliver the powers outlined in the Vow, and on which he was one of two Conservative representatives, stated that “we should go beyond Smith”, and proposed replacing the Act of Union with a new and much looser one . Boris Johnson, possibly the next Conservative leader, backs federalism , as do several other significant figures such as Murdo Fraser, former Deputy Leader of the Scottish Conservatives . Of course, actions speak louder than words - David Cameron’s support for the Vow as well as English Votes for English Laws has brought about our transition to a quasi-federal state. First Minister Nicola Sturgeon already serves as a national spokesperson for Scotland, while Scots have been stripped of representation at Westminster on many issues through EVEL. The Union is being systematically dismantled by supposed unionists.
The ‘big three’ aside, a few words should be said on UKIP. Many might have hoped that they would stand up resolutely for the Union, and take a more overtly pro-Union, pro-British stance than the Conservatives might be willing to do. Unfortunately this has not been the case, chiefly because of the English nationalist element within UKIP who, much like their nationalist counterparts in Scotland, have been aggressive in pushing for devolution and the federalisation of the UK. UKIP Deputy Leader Paul Nutall has stated that “we have come to the conclusion that we need a federal UK”, while calling for an English parliament . Nigel Farage similarly announced that “we now as a party believe in an English parliament, and actually believe in a federal structure for the United Kingdom”.  He later expanded on what this would involve, which included the termination of any Scottish representation in the House of Commons, and its transformation into an English-only parliament. So much for parliamentary union.
The nature of federalism, quasi-federalism, and their unanimous support throughout the mainstream so-called unionist parties has been detailed above. Some thought should be given to why they support such radical constitutional change, and why the Unionist Party opposes it. The support for federalism/home rule in the case of Scottish Labour is because of their antipathy towards Britain, Britishness and the prospect of Tory governments in Westminster. In the case of the Lib Dems, it is due to their wider ideal of decentralisation, and fits neatly with their drive to be as compromising, uncontroversial and non-offensive as possible to nationalist and unionist alike. In the case of UKIP, it is due to pressure from English nationalists demanding devolution in England and who are aggrieved at the UK’s regions seeming to get preferential treatment. In the case of the Conservatives, it’s a mixture of the pressures felt by all these parties. The important thing to note in all cases is that federalism is not adopted out of any deeply held conviction to keep the UK together, but rather as a response to external pressures, and often a knee-jerk one at that.
Indeed, it is clear that federalism could not possibly do anything to strengthen the Union. Constitutionally speaking, it involves a radical weakening of the Union and essentially gives home rule to the four home nations. The most worrying thing, however, is that it would almost inevitably lead to independence. If we were to look at Scotland alone, in a federal UK the Scottish Parliament would be entirely responsible for health, education, social spending, and all the positive roles of government that are central to the SNP’s vision of a centre-left Scotland. Tax and spend would take place almost entirely within Scotland, thus re-orientating the pooling and sharing of resources and the sense of national and economic community to the Scottish rather than British level. In contrast to the positive duties of the Scottish Government, the federal UK parliament would be responsible only for things like defence, immigration and foreign intervention. These are often the unpopular and contentious issues, and the SNP could easily portray such a government as nasty, right-wing and having no mandate in Scotland. Federalism would create a situation where all the Scottish Parliament does is provide public services, while all the British Parliament does is run Trident, detain refugees and bomb Syria. That is certainly how nationalists would frame it, and it is hard to see the Union lasting under those circumstances.
All this, of course, is merely an extension of the devolution process that has been leading us down the path to separation since the introduction of the Scottish Parliament in 1999. All the dangers mentioned above apply also to the present situation under devolution, only to a slightly lesser degree. That every mainstream unionist party is intent on going even further down this path is deeply concerning. Federalism and quasi-federalism are radical attacks on the nature of the UK as primarily a unitary state, which it has been since its inception hundreds of years ago. The proposals coming from the mainstream unionist parties are barely less radical than those of the SNP, and show little more commitment to defending the Union. If we want to defeat separatism in the long-term, then we must reverse the ongoing breakup of the UK and reintegrate Scotland into British political life. This will only be achieved through closer union, not further separation, and there is only one party that will be making such a case this May.
 https://www.smith-commission.scot/wp-content/uploads/2014/10/Scottish-Liberal-Democrats-Submission-1.pdf, page 3