One of the struggles of our age is between the professionals who claim politics is all about responding to detailed polling, and the amateur democrats who believe politics should be about principles and judgement.
Some claim the way to “do politics” is to poll the marginal seats and the marginal voters, finding out exactly what they want to hear, or even want they want from government, and giving it to them. If you take this approach to extremes a political party that wants to win a General Election has its policy and its statements dictated by small groups of voters in highly marginal seats.
Others are high on principle but short of votes. They set out what they believe and want, and leave it to chance and to the electorate to see if they win any or enough seats.
As these caricatures suggest, a successful party or candidate needs a bit of both. You do not win if you are unwilling to reach out beyond your core support. You are unlikely to be trusted to govern if you never compromise and merely represent a minority group of the electors. You are also unlikely to be trusted to govern if enough people think you are prepared to change your views and policies every time a poll shifts in crucial marginal constituencies.
People do expect some consistency of approach. Governing is different from crafting electoral messages. Governing well is the best way to get re elected. If you govern well much of the message takes care of itself. It still helps to have a good way of explaining what you have done and what you want to do next. Governments also have to remember that a good record is only part of the offer. People are more interested in what you will do for them in the next Parliament than in what you have done for them in the last. If you have governed well they are more inclined to listen favourably to your offer. If you have governed badly it will be difficult to get their trust for what you want to do next.
One reason why polls often improve for a government as an election approaches is people change they way they judge. Between elections people tend to judge a government by absolute standards. Could they have done better? Could they have backed what I wanted ? Could they have avoided that mistake? As an election approaches people are reminded that it is a contest between two very human groups of people to govern. The contest is then an easier one for the government. The question shifts. Not did they do well by absolute standards, but did they do better than the other lot?
Conservatives will win more votes from the success of the economy in generating jobs and fostering gr0wth than they will from any clever message. As always a party needs to balance its principles, its core voters, and its outreach to new voters it needs to attract. Polls are relevant background, but should not determine what the party does or says.