With the US presidential election approximately around three months away, voters in twelve key states are being subjected to an unusually early flurry of negative television advertisements.

The ads, highlighting the other candidates' mistakes and vulnerabilities, are paid for by campaign teams and their supporters.

But a new poll suggests voters are growing tired of the negativity beamed into their homes day after day.

Looking through a series of negative ads, the first thing that strikes me is that almost without exception they're nasty, passive aggressive, mean-spirited and only partially true - yet they're the centre-piece of modern US elections.

At this hour, Americans living in battleground states like Ohio, Florida, Colorado and Virginia - the ones with enough swing voters to determine the outcome of November's poll - are being subjected to an onslaught.

One that promotes likely Republican presidential candidate Mitt Romney asks: "When a President doesn't tell the truth, how can we trust him to lead?

In another that supports President Barack Obama, a wildly out of tune Romney can be heard singing the national anthem, while on the screen the words Swiss bank account suggest where he keeps his millions.

And the mud is sticking to both candidates.

According to a new NBC/WSJ poll, the President is viewed negatively by 43% of voters, his second-worst rating since taking office. Romney's negative rating of 40% is the worst this poll has recorded for him yet.

But by big margins, voters say the bulk of information they've received from both campaigns in the last few weeks has been overwhelmingly negative, with Obama's campaign being viewed as slightly more negative than Romney.

"Nasty, nasty, nasty," says Sergio Bustos, a writer for the Miami Herald.

He says in Florida, which is a key bellwether state, the airwaves are already full of very negative advertising.

"Mostly from Obama at this point, but Romney's ads are also coming in and they're all equally negative. It's going to be a very, very ugly campaign," he said

The NBC/WSJ poll suggests both sides are as bad as each other ... with voters who were asked saying President Obama's side was slightly worse than Mitt Romney when it comes to negativity.

So, will things change? Unlikely, I feel. With such a large electorate, television is the only way to reach all the voters, and the bottom line is that while Americans complain about them, all the evidence suggests negative advertising actually works!