Original sentence: Because the votes of swing voters are considered to be "up for grabs", candidates direct a fair proportion of campaign effort towards them, although they must also be concerned with voter turnout among their political base.In an election, there are "certain" or "lock" votes - voters who are solidly behind or partisan to a particular candidate and will not consider changing their minds whatever the opposition says.In the United States, they may be dissatisfied Republicans or Democrats who are open-minded to the idea of voting for other parties, or they could be people who have never had a strong affiliation with any political party, and will vote depending on certain things that influence them - e.Some might be people who have never exercised their right to vote before, such as those just reaching voting age.Swing voters are undecided about how they will vote.They are sometimes referred to as undecideds or undecided voters, but floating voter is now the more common term used for this kind of voter.healthcare, benefits, election campaign etc
Edited sentence: Because the votes of swing voters are "up for grabs", candidates direct much campaign effort toward them, although they must also be concerned with voter turnout among their political base.In an election, there are "certain" or "lock" votes -- voters who are solidly behind a particular candidate and won't consider changing their minds no matter what the opposition says.In the United States, they might be dissatisfied Republicans or Democrats who are open to the idea of voting for other parties, or they might be people who have never had a strong party affiliation.On the other hand, swing voters are undecided about how they will vote.Others might be people who have not voted before, such as those just reaching voting age.They are sometimes referred to as undecideds or undecided voters