Theresa May was right to call this snap election, and the public agree. In fact for every one person who doesn't think it's the right thing to do there are three who do, according to a recent YouGov poll. When she wins the election, hopefully with a much greater majority, she will have a mandate to go ahead with Brexit in the way she is putting forward - i.e. leaving the single market, taking a hard stance on immigration while getting "the best possible deal for Britain". It will prevent the Lib Dems, and other opposition, from claiming that the people didn't vote for "hard Brexit", as they call it, because May will be able to hold up her election pledges (which should clearly outline her plan for leaving the EU) which will have been endorsed by the public. The opposition will still be able to scrutinise May's decisions and hold her to account, but importantly the people will have endorsed her Brexit.
However, with this great new mandate May will have will come the pressure of sticking to her manifesto and fulfilling the pledges she makes. Too often this isn't easily done domestically - promises broken by those in government regularly dominate headlines. The fact that May will be negotiating with 27 other countries to deliver the Brexit she's been elected to deliver will make that all the more difficult.
Restrictions of immigration, for example, won't be easy to achieve. I saw in a newspaper headline saying she will bring back the promise to reduce net immigration to the "tens of thousands". If this is true, it could prove to be a big mistake - like it was for Cameron. Clearly reducing immigration isn't an easy task. May should be able to end free movement with EU countries, but even then there will be pressure from the 27 to keep it for a short period afterwards as well as domestic pressure (from businesses, and likely the political opposition) to do a deal which allows easy movement between the UK and the EU. On top of that, immigration from outside the EU is in the hundreds-of-thousands. Reducing it would be a mammoth task within itself, and certainly not something May will want to contend with while trying to make a success (or prevent a disaster) of Brexit. Even if this isn't promised in the Conservative manifesto, it's a good example of the type of thing that means we'll be able to hold her government to account on.
Away from Brexit, with the different direction May's government is heading in comparison to Cameron's, a general election is, again, the right thing to do. May won't be bound by the promises the previous administration made and she'll be free to lead her government in her own direction. Plus, May will no longer be the "unelected Prime Minister", as the opposition parties like to say, but will have secured her own mandate to lead the country.
There are those who say the election is purely political opportunism. This plays a role, but for the reasons I have mentioned above I don't think the election was called just to win more seats. Still, is it such a bad reason to hold an election? May is polling unprecedentedly well. And this isn't just down to the useless and weak opposition Corbyn's Labour is providing (though be in no doubt, his opposition is useless and weak). May and her team have carefully and successfully crafted a statesman-like image of her. They've done well to contrast her as being as effective, decisive and stable Prime Minister against a chaotic Jeremy Corbyn who is the complete opposite. Moreover, her policies generally go down well. Grammar schools, for instance, are actually quite popular, and she polls well when the public is asked if they are confident she can make Brexit a success.
Theresa May should lead the country to the biggest Conservative majority since Thatcher led the party. But the real hard work starts after the election. Once she has a mandate on how to deliver Brexit, it will be clear to the public (and hopefully Labour and the Opposition) where she goes wrong and breaks promises. For numerous reasons, this election is the right thing to do. Yet further down the line it may still backfire.