Freddy Gray suggests  that Britain’s snap general election could be more difficult for May and the Conservatives than many expect:
But this general election will prove much more challenging for May than the polls make out. Her opaque Brexit agenda will come under ever increasing scrutiny, and she will have to face the ongoing problem of the Scottish National Party. Led by Nicola Sturgeon, the SNP wants to use the fact that a large majority voted to remain in the EU as justification for a second referendum on Scotland’s independence from the UK—just two years after losing the first. May has resisted those efforts so far, but if the SNP makes further gains north of the English border on June 8, it will become harder for her to keep saying “now is not the time” for Scottish nationalism.
Labour, moreover, is not as weak as analysts often assume. Corbyn may be daft, and as far to the left of the British mainstream as Bernie Sanders is to America’s, but voters are less and less predictable and Labour’s support is more resilient than many polling firms recognize.
If previous results in Britain over the last few years are any indication, a large Tory polling lead six weeks before the vote doesn’t necessarily mean there will be a large Tory win. It may not have a big impact, but I would think that May’s arbitrary reversal  on her pledge  not to call for a new election before 2020 has to annoy and alienate more than a few voters. James Forsyth observes  that May could be damaging her reputation by doing this:
Much of the May brand, and her appeal, is built on the idea that she is a grown-up who gets on with the job and doesn’t play political games. By going for an election, and especially when the Tories have a record poll lead over Labour, she endangers that.
May’s decision to call for a new election is the act of a supremely confident (possibly overconfident) leader, but if there’s one thing she ought to have learned from her predecessor it is that voters have an odd habit of not cooperating with a politician’s plans. Cameron thought he could use a Scottish independence referendum to bury Scottish nationalism forever, and instead provided the nationalists with an opportunity to become stronger than ever. The No campaign won the vote then, but the nationalists won Scotland and are now angling for a second referendum sooner rather than later. Cameron also thought he could hold an EU referendum to placate Euroskeptics in his party for his own purposes, but never considered the possibility that the referendum would lead to a victory for Leave. In the end, he lost his gamble and then resigned. May’s gamble now is that voters will reward her party with a greatly increased majority in an election that she promised wouldn’t be happening for years. Her gamble may pay off, but recent experience makes it seem more likely that this ploy will blow up in her face.
No doubt May has many advantages going in to the election, including a hapless opposition, and the Conservatives will probably gain some seats. Even so, we shouldn’t forget the extent of popular hostility to the political class that last year’s referendum showed, and if that mood still prevails it could be bad news for the ruling party.