These are good points. There i think will be an issue in the case of a 'deal' scenario that is 'Norway-esque' (Which i believe is somewhat where the UK if May gets her way will end up if/when the EU negotiates her down from the original chequers position)- while protecting somewhat the economy, actually delivers less sovereignty indeed than when we were a member due to as you say it being waved by having no say in the rules or the running of the union which we've signed up to. I'm not sure though what the electoral consequences for the Conservative party will be here though, as brexit for them in the ways being lacked at is very much 'lose, lose'. On the other hand for instance, a brexit that is a Canada Style deal, which is also likely, but that excludes service, specifically financial- will have an adverse impact on Britain's economy (affecting the perceptions of the Conservatives who have made the negotiations 'their baby' for the majority of the public who aren't ideologically aligned to leave or remain) and will also really peeve off the Conservatives traditional core support and funders in the City. Though iirc a deal would be popular among many of the Conservative associations around the country- making this a huge mess essentially for them politically. I do give some credence to the commentators who are talking about brexit being the death knell of the Conservative party (added to brexit the domestic agenda issues), however, FPTP also makes this unlikely realistically, and i can't see Corbyn getting a Blair-esque landslide that would consign the Conservatives to opposition for the next decade- of course it may happen- again i'm not going to place money on anything, But i think the two-party system will prop up the Conservatives, as seen by their brexiteer faction consistently backing away from their threats to topple May, or indeed 'split' and form their own party- as the former would lead to probably a softer brexiteer or remainer getting the premiership, and the latter would see any such new party punished severely due to FPTP- as the brexiteers lack the parliamentary numbers in either scenario to make it work. So i think in this context of the Tories damned if they do, damned if they don't- all types of deal are on-the table pragmatically- its just who gains 'control' of the party, Brexiteers, May, Or Remainers.
Your right too about the big contention to the deal being freedom of movement. Its been exacerbated by the DUP and the N.Irish border being made such a political issue- May's red lines here actually being a huge drawback to a pragmatic solution (I'm sure we all still remember her being on the verge of signing an argreement with the EU that would have significantly resolved the issue and led to progress, before at the last minute the DUP literally dragging her back to the UK to dress her down, and the subsequently her position changed). I suspect though given the current political situation we're heading for the Norway-type deal, or (ironically and in complete contrast) are in danger of crashing out on WTO- which i tend to agree with Caratacus about- we've messed around for two years and are not remotely prepared as we should have been for the consequences of that. Either way though, the Conservatives are going to suffer- if this will benefit UKIP or not (Perhaps even with defections? Though i again doubt any Conservatives would be ready to sacrifice their career for their principles based on how things have developed currently) i'm not sure. I suspect to make a safe-guess, post-brexit UK politics might be dominated by coalition arrangements or continued 'unstable' majority governments, possibly from Labour, though if Corbyn does step-down, and Labour keep the same policy platform (He being divisive, his policies though being universally supported)- then the magic of Blair may rear its head again.
Speaking of which the idea put forward by Blair for a new 'center party' in UK politics- specifically to combat a hard-left domestic agenda and a hard-right brexit- as he puts it- i think is a dead duck
. Not that centrism is 'dead' per say, but that the UK currently requires radical solutions for its myriad of issues and i can't see this gaining traction among the electorate due to this point. I assume this party would have the same position on brexit as the lib-dems- i.e. against Brexit, while also having the same 'pragmatic' compromise policies on how to do things domestically- the issue being thus far this combo hasn't exactly worked for them.. and i can't see it working in the near future for anyone else. So the potential for Bannon to have a competitors in Blair- both trying to forge new parties and European supergroups is not there, and political commentators will have to alas sulk that the two will not be locked in some titanic struggle for the heart of Europe
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