Theresa May no doubt called an election because she thought it would be good to get a mandate for her style of Brexit and her own personal mandate as Prime Minister.
But she also clearly had a keen eye for a tactically good time to call the election. The Labour party is weak and Jeremy Corbyn is unpopular. And neither the Liberal Democrats or UKIP have transformed themselves into vote-winning machines yet, as far the polls can measure.
But the extent of the Conservative strength is not always fully understood. Here is a striking graphical image which conveys both the current political landscape, and the power of Theresa May's position.
The battleground graphic shows a two-dimensional representation of the possible outcomes. The horizontal axis represents the Conservatives' vote share over the range from 30pc to 60pc. And the vertical axis represents Labour's share, which runs from 10pc to 40pc. The current opinion poll ratings are approximately centered in the middle with the Conservatives on 44pc and Labour 24pc.
The Conservatives gain if the marker moves towards the bottom-right corner, and Labour gains if the marker moves towards the top-left. The Liberal Democrats (who are set to equal 79pc minus the sum of the other two parties) gain if the marker moves to the bottom-left. The other parties (UKIP, Green, SNP, PC) are assumed to be fixed.
The current position is in the middle of the block labelled "Con maj 100", which represents election outcomes where the Conservatives get a majority between 100 and 200 seats at Westminster. This position gives a Conservative majority of around 130. The striking point about this picture is the large size of the buffer zone around this outcome. Public opinion has to move a large amount to overturn the projected Conservative majority.
Further towards the Conservative corner in the bottom-right are the zones of ever-increasing Conservative majority. The "Con maj 200" zone is for a Conservative majority between 200 and 300 seats, and similarly for "Con maj 300" (300 to 400 majority) and "Con maj 400" (majority of 400 or more). In the Labour direction, the light blue "Con maj" zone is for an overall Conservative majority of less than 100 seats.
The nearest non-blue zone is "Con & Lib/Nat" which is the biege region representing a minority Conservative government which has the freedom to choose either the Lib Dems or (unlikely) the SNP as a coalition partner. But even that zone is about 7pc away from the current location if you move left and up. That requires a fairly large swing and/or a large poll error.
Further away is a marginal zone, coloured yellow and labelled "Con/SNP". This is swampy territory from a constitutional point of view, because the Conservatives would be the largest party but without an overall majority, and the Lib Dems would be too small to be a coalition partner. The Conservatives would either have to have an unholy alliance with the Scottish nationalists or try to soldier on as a minority government. Labour needs a swing of around 8pc away from the Conservatives to get into this area.
Down in the bottom-left corner, the Liberal Democrat stronghold, there are small zones which represent minority and majority Lib Dem governments. Getting Tim Farron to be Prime Minister requires a swing of around 15pc from the other two parties to the Lib Dems. Lib Dem supporters may hope for this, but that is a very long distance in political terms/
Finally, in the top-left corner there is a small patchwork of red areas. These all represent minority Labour governments with one coalition partner or another. Labour would need a swing of around 12pc to get here and have Jeremy Corbyn in Number Ten. Strikingly, there is no territory within 15pc of the current location which represents a majority Labour government.
The key message of this picture is how safe the Conservatives appear. There can be a 5pc swing against them in any direction, and they will still have a comfortable majority. Amazingly, there is more territory on the map representing a Conservative majority above 400 than there is for a Labour majority government.
During the course of the campaign we will hear about many other electoral effects: tactical voting, "Remain Tories", anti-Conservative local pacts, the youth vote, turnout, Labour's bedrock support, and so forth. Some of these may make a difference, and this column looks forward to addressing the important factors in later weeks.
But the big picture is that the starting position is very, very good for the Conservatives. And something big has to happen to change that.