Jeremy Corbyn is in Wales today. On the agenda: his ambitious plan to build more houses (an England-only issue as housing is devolved in Wales), more money for schools (devolved in Wales), and an expansion of free school meals (also devolved in Wales).

It’s an exact echo of the problem with Boris Johnson’s big strategic priorities: the government’s domestic policy messages all relate to issues that are fully devolved in Scotland, and to a significant measure in Wales.

My anecdotal impression is that there are really only two areas that are generally known to be devolved in Wales. The first is the National Health Service, in part because of a prolonged campaign by the government of David Cameron to blame healthcare outcomes in that part of the United Kingdom on the Labour government in Cardiff rather than the Conservative one in London. The second is the funding and preservation of the Welsh language, both for positive reasons and because of the still-strong streak of anti-Welsh language racism in parts of Wales.

It’s also less of a problem because if your main opponent is also campaigning on devolved issues then you are less likely to be punished for it. In most Welsh marginal constituencies the battle is a Labour vs Tory one, so the downside risk is perhaps lesser. But that also exposes the ridiculousness of the situation: both Boris Johnson and Jeremy Corbyn need to do well in Wales at the next election to form a government, or at the least in order to form a stable administration. Yet neither has used their visits to the country to focus on signature policies that would improve the lives of Welsh people.

There are a couple of things to watch out for. The first is that Corbyn’s ability to go to Wales and be cheered for talking up education is a product of two failures: a general media failure and a specific strategic failure by the Welsh Liberal Democrats, who have been running education as part of their coalition deal with the Welsh Labour Party for three years. By now they really ought to have a list of achievements that they can rattle off and that are widely known at least among politically engaged Welsh voters.

That strategic failure might take care of itself. That the Welsh Liberal Democrats are sharing power with the Welsh Labour government (and in the eyes of most people at the top of both parties, making a decent fist of it) is a useful talking point for Liberal Democrats everywhere when they encounter criticism of them as a party that went into coalition with the Conservatives. Just as Cameron’s attacks on the Welsh NHS were primarily intended to deflect attacks made by Ed Miliband in England but changed political perceptions in Wales as well, it’s possible that a by-product of a Labour-Liberal Democrat row in England might in the long term be to increase awareness of what the devolved administration is up to in Wales.

It’s also in Plaid Cymru’s longterm interests to talk up what distinguishes Wales from England, which will also make it harder for the big two to get away with rocking up in Wales with a series of policy pledges that don’t apply to that country.

So just because both parties are getting away with it at the moment doesn’t mean they will get away with it indefinitely. But the bigger immediate problem is this: I don’t think it is coincidental that the Conservative and Labour leaderships are both seemingly unaware of what is devolved in Wales and look badly adrift as far as public affection in Scotland goes. As far as Tory fortunes are concerned, that could result in serious losses to the SNP, imperilling their hold on power. From the perspective of entering Downing Street, it doesn’t really make any difference to Corbyn’s hopes if a Scottish Labour MP is replaced by an SNP one, but it will make a difference to how stable and probably how long-lasting any Corbyn-led government is.

In both cases, the two parties have serious reasons to step up and develop distinct messages for the devolved nations.