One Man One Vote Is Important

The principle of one person, one vote is the cornerstone of democracy ....

One Man One Vote Is A Basic Tenet Of Democracy

..... If that is threatened then the very foundation of the system collapses.

In fact it was allegations that this basic principle was being abused in some states in the USA, that led to the false claims that the Presidential elections had been won by fraud, and eventually to the Capitol Hill invasion.

So any attempt to weaken the safeguards, such as letting people not registered vote (such as unregistered or illegal immigrants), or postal votes being farmed in some communities (where women's votes are basically stolen by 'community elders' or males in the household, and used by them), has to be severely dealt with by criminal proceedings or unexpected consequences for the whole process can ensue e.g. the aforementioned Capitol Hill invasion.

Voter registration drives, usually aimed at teens or certain ethnic groups, may seem like democracy in action, but nearly always are motivated by the political considerations of the groups supporting it. This is because teens and ethnic minorities usually vote in larger numbers for left leaning and socialist parties.

US Votes By Voter Age

For example in the USA, 62 per cent of voters aged 18 - 29 voted Democrat, while only 35 per cent voted Republican in the 2020 Presidential election ... some report the figures as a 61 per cent versus 36 per cent split, but the difference is the same.

US Vote By Race ...

While ethnographically, according to exit polling in the 2020 Presidential Election in the United States, 87 per cent of surveyed Black voters reported voting for former Vice President Joe Biden. In the race to become the next president of the United States, 57 percent of white voters reported voting for incumbent President Donald Trump.

So voter drives aimed at these two groups (ethnic minorities and younger voters), in the USA, are quite clearly going to benefit the Democrats rather than improve democracy (which is more of a secondary benefit). Hence the battle over this in the USA. These outcomes and considerations apply equally in the UK, and analysis of the last General Election results corroborate this fact.

Vote By Age UK

In the 18 - 29 voter age range, the Labour Party can expect to get over 50 percent of the votes cast, with the Conservatives getting under 25 per cent of the votes. And amongst the ethnic minority voters (which although often diverse in their voting patterns, can be lumped together just for this comparison), estimates by polling organisations suggest that Labour won the votes of 64 per cent of all Black and Minority Ethnic (BAME) voters, while just 20 per cent voted for the Conservatives and 12% for the Lib Dems. So of the seats that had large BAME populations at the 2011 Census,  Labour won in 113 seats that had a larger-than-average BAME population, while the Conservatives won 53 and the Lib Dems four.

UK Vote Age And Gender

Its a fact that as voters get older (and perhaps more common sense haha), the voting trend amongst voters (particularly white voters) shows the voting preferences reverse, and the balancing point in the UK for this bias in voting is actually aged 38 (when votes are nearly equally split between left and right)  .... which surprised me, as I would have guessed about 10 years earlier.

Oddly when looking at voting by the sexes, both men women in the UK are more likely to vote for the Labour Party than any other party up until the age 50, but by an increasingly much narrower margin as you approach that upper age. But after that age, men and women are overwhelmingly more likely to vote for conservative or right leaning parties. The current age weighting in the UK population towards older people means that this pushes Labour away from winning the elections. 

These age and sex demographic voting patterns are similar (although not quite identical) in the USA, but in the over 65 age group Trump won 51 per cent of the votes, against 48 per cent for Biden (they split 50 - 49 percent in Bidens favour in the 45 to 64 voter age group) ... in the 18 to 44 age range Biden clearly won most votes. 

So obviously, for the left leaning parties, the idea of younger voters or ethnic minorities being targeted for voter registration is important, because the natural ageing of populations (around the globe) favours the right leaning parties for the next couple of decades at least.