Similarly, heavily Democratic or Republican legislative or Congressional districts are downplayed in significance.
Because of the negative effects on minority parties in ignored or downplayed constituencies, targeting is becoming increasingly controversial.
For example, usually the marginal constituencies in the Midlands receive far more attention from campaigners than either Surrey or the North-East, as they are solidly Conservative and Labour strongholds respectively.
Canada, which has seen regionalism play a role in its national politics, will see odd targeting patterns, where a province, Alberta for example, might be ignored by a party which usually does not do well there, the Liberals for example, while an Edmonton, a large city in Alberta, will see heavy targeting as the Liberals attempt to win at least some representation from that province.
The biggest contrast with the US system is the idea of a “Full Slate”; That is running a candidate in every possible seat.