1. The backstop is a part of the divorce deal. Since UK is heading straight into a no-deal Brexit, this part also falls through. In other words, with a No-Deal Brexit, the Backstop also automatically drops off the table and thus the UK is not part of the Customs Union anymore then in any way, and will have to pay import taxes if they want to export to the EU.
2. They have no say, but it's the NI Secretary of State's duty to perform such polls. Also, it's her duty to reflect on people's interests
4. No need for such security. Besides, if the Troubles come back, they happen in Northern Ireland, so it would rather be in UK's interest to raise the wall sky-high instead of Irelands to keep the Nationals from supplying themselves with everything they need. For the rest, look at point number 1
5. Leo is right in a way, as it would keep the spirit of the GFA, but not the letter, which doesn't say anything at all about or against border controls, So these can be put in action without breaking the agreement.
LurkerJ already posted the collateral, with some jobs being lost on the continent as there will be slowing trade with the UK for a while at least. The economy of the EU will get a small hit, but nothing near the hit it will be for the UK.
1. Is being a part of an indefinite customs union a part of that deal as well ? If it is then the ERG are right in that the EU can go kiss their own asses ...
2. It's also the duty of NI Secretary of State to determine the requirements for the polls and she isn't to be held accountable by the people but the prime minister itself ... (just by the virtue that it is the unionists alone who have a decisive advantage in both votes and representation of NI constituencies means that there's no clear majority to hold a border poll)
4. Pretty sure there would need to be security because the extreme Irish nationalists wouldn't be attacking British border patrol officers (UK probably won't send any before Ireland does) but they'd be attacking Irish border patrol officers! Then there's also the issue of there being over hundreds of crossing points and Ireland was FORCED TO BLOCK the vast majority of the crossing points because they've suffered many more breaches on their side so if Ireland is to so much as to block even just a SINGLE crossing point they'd automatically void the GFA. During the Troubles only 20 crossings were open while today there are as many as 275 crossings so I doubt that Ireland will be able to effectively police all of them ...
5. Again Ireland CAN'T BE BLOCKING the crossing points since it would be in absolute breach of the agreement ... (they need a hard border or they get kicked out of the customs union)
The UK will be taking more than just some jobs on the continent. It will also either enable smuggling or result in Ireland getting kicked out of the EU customs union. How is one supposed to deal with the nationalists feeling betrayed in the process and the numerous crossing points ... (for Ireland it's either all or nothing regarding a border so they can't just have a 'soft' border like only a customs check as it would still open the possibility of smuggling)
1. The backstop was planned for a period of 21 months, until end of 2020 (that's the one in the deal, set up until a definitive solution could be found), not indefinitely. The indefinite one, where the UK parliament would have had the last say on any agreement, got shot down by the EU.
4. Why would they attack Irish customs officers (because that's all that's gonna be needed on the border, no military officers) but not British ones? That makes no sense at all, especially since the Brits leaving the EU is the cause for this mess in the first place. I agree on the streets that got reopened after 1993, they probably will need to be blocked again. But again, making a road impassable doesn't mean militarizing a border. And again, that doesn't void the letter of the GFA.
While we're at it, Ireland leaving the EU wouldn't solve any of these problems, the only thing that does is Northern Ireland becoming part of Ireland again
5. Again, Ireland has every right to do so as long the border doesn't get militarized, Besides, custom checks on both sides are gonna be mandatory after a no-deal Brexit. Or let me quote from another source: " in a no-deal Brexit scenario, the EU and the UK must trade with each other in line with the MFN obligation. The EU would have to treat goods coming from the UK in the same way as any other third-country goods. Likewise, the UK, following a re-negotiation of its Schedules of Concessions and Commitments on goods and a settlement of its regulatory environment with the EU and all other WTO members, would be required to raise duties and conduct border requirements without distinguishing between products originating in the EU or any other nation. Unless and until the UK negotiates new preferential trade agreements with other countries – including the EU – the country will have to trade goods on a MFN basis. As a result, at the land borders with the UK, as well as at EU ports and airports, the EU will apply the same border checks for goods originating in the UK as it does for goods coming from any other non-preferential trade partner. Absent an agreement between the two blocs, goods crossing the North/South Irish border or arriving by sea or air will be subject to EU customs duties, VAT and excise duties, as well as EU rules of origin, EU product safety and quality standards, EU sanitary requirements for live animals and products of animal origin and EU environmental protection and animal welfare rules. By the same token, the UK will have to apply its MFN duties and border controls on goods coming from the EU."
In other words, both the EU and the UK will have to impose and enforce border checks. I already explained that those don't break the GFA several times. And, as you can see, since the UK is also forcing themselves to border checks if they go No-Deal, even if border checks would break the GFA (which, again, it doesn't!), then both would have to break it, not just Ireland. In fact, the UK are already preparing themselves to create a hard border with Ireland. No exception from Articles 21 and 24 either, by the way: "The pivotal non-discrimination obligation enshrined in Article I GATT 1994 therefore casts doubt upon the position of the UK Government and the arguments of some Brexiteers mentioned above. In the event of a hard Brexit, the WTO MFN principle will entail a hard border between Ireland and Northern Ireland. Exceptions such as the national security exception under Article XXI or the frontier tariff exception under Article XXIV:3 GATT 1994 will not apply. Unless and until the UK and the EU conclude a preferential trade agreement such as a free trade agreement or a customs union as authorised by Article XXIV, a hard South/North Irish border will remain."
Also, if you're so concerned about smuggling into the EU, how about smuggling into the UK instead? The EU has much more and cheaper goods to send into the UK than what the UK has to offer. In other words, the UK will need to install border checks, too. For instance, smugglers are getting ready to smuggle cigarettes en masse into the UK