You demonstrate that you have no idea what you are talking about, but you are doing it in the wrong thread. How about talking about the UK election in the UK election thread? If you don't know the importance of government policy being in its manifesto, in terms of getting its business through the Lords, then you don't know anything at all.
I'm at a loss why you think I'm arguing this in the wrong thread. It is germane to this thread, and it was you who raised the topic here in this thread.
And you evaded the question that I raised, so I'll try again.
The Salisbury Convention says the Lord cannot vote down a bill that was announced in the election manifesto. But the manifesto has to be specific on what the bill will entail. The Tories can't just write into the manifesto, in Trumpian fashion "we'll negotiate the bestest Brexit deal"; they'll have to say what that deal will contain.
So, let's look what the May government just two months ago announced as their intentions in the White Paper. I pick out just two points:
1) wide-ranging free trade with the EU
2) the UK has full control over immigration from the EU.
So, those points will also be in the Tory manifesto.
Fast forward to March 2019. After tough negotiations, May presents a Brexit bill that has
1) passporting for financial services, but no free trade for other services, nor for industrial or agricultural/fisheries goods
2) the UK must allow immigration of at least <insert 75% of current level> from the EU countries.
3) and the UK must pay the EU GBP 200mn/week for the privilege.
Obviously, this Brexit deal does
not conform to the election promises in the manifesto, so it's also not subject to the Salisbury Convention.
I just made up those hypothetical negotiation outcomes; but the White Paper is totally unrealistic in its aims. It reads like a letter to Santa. No way that the UK government will achieve the goals outlined therein. So no matter how the negotiations exactly turn out, it will not look like what is in their manifesto, not even close, and thus the Brexit bill will not be subject to the Salisbury Convention.
Or, alternatively, the Tories would have to greatly turn down their expectations and write much, much more sober aims in their manifesto.