Ahead of the US elections, BBC Washington correspondent Katty Kay has answered your questions in a live Twitter Q&A on Thursday 25 October.
This is an edited version of the session.
John in Scotland emails: Is it not the case that USA's presidential election is a totally money driven event?
Katty answers: $2 billion will be spent on this campaign but events matter too. His victory at the Denver debate didn't cost Romney a cent.
Question from @Evolve69: Why are US ballots so complicated? Why not a simple, identical, nationwide ballot with candidates names? Cheers.
Katty answers: Because each ballot has the presidential & all the local candidates as well.
Question from @TheFreeMason: Never mind what the polls say, who's REALLY in the lead at this point?
Katty answers: Short of a crystal ball - we sort of do have to rely on the polls. Sorry. But I think it is neck & neck
Question from @MikeBgolfing: 4 years ago Mitt got smoked in the primaries. What has changed to make him a viable candidate now?
Katty answers: Voters are disappointed with Obama. Romney has economic credentials & being the GOP nominee automatically gives him status.
Ewan, Scotland emails: In the event of a tie, what happens? Could President + Vice-President come from different parties?
Katty answers: If it's 269 to 269 electoral college votes, the House of Representatives chooses the president and the Senate picks the vice-president
Question from @sophie2709: Should US voters consider the world's view, which gives Obama the most backing internationally?
Katty answers: It's complicated. In 2004 Bush used global antipathy towards him to win support at home. But having friends abroad is useful.
Question from @_Stephen_Adams: There have been more female than male voters in every election since 80. Will women decide this race?
Katty answers: The campaigns seem to think so! More women vote than men in US elections, so Romney & Obama are fighting hard for female support.
Question from @Mysterion3000: From the photo, it looks like your BBC News US office needs more natural lighting.
Katty answers: It needs more everything!
Question from @strmrgn: Which Senate race do you feel is the most important to watch, and will the Democrats retain control of the senate?
Katty answers: We are watching six key Senate races. I'm focused on Massachusetts. It looks like the Democrats will hold the Senate
Andrea in the Netherlands emails: Could adverse weather like snow or hurricanes tip the balance in swing states on the day?
Katty answers: This election is so tight that yes I think snow, rain, or Sandy could affect turn out and the result.
Question from @lucyglewis: Which candidate do you think has the most momentum behind them at this stage?
Katty answers: Romney has had momentum since the first debate - I do know Obama campaign is watching this very closely.
Will Gorman in UK emails: Why were both so defensive when another candidate questioned their commitment to Israel?
Katty answers: US sees Israel as key ally in Middle East but no one running for President wants to alienate the power and money of the Jewish lobby.
Question from @redkoko: How does Romney winning election change USA/UK relations? International opinions on Romney?
Katty answers: Romney didn't win himself any friends in London - but I think the relationship will still be special, essential and strong.
Question from @rhysdgriffiths: Do you think it's a shame the other four tickets on the ballot get absolutely no airtime whatsoever?
Katty answers: It is a 2 party state and they won't win but the BBC has covered them.
Question from @Bergomi134: Why is Ohio so important/integral to the US Election?
Katty answers: Ohio is a microcosm of US. It has agriculture, manufacturing, energy, rural and urban areas. No Republican has won White House without it
Lars Tornfeldt in Sweden emails: Can Mitt Romney swear the presidential oath on the book of Mormon.
Katty answers: It would be a first! But unlikely. He took the oath as Governor of Massachusetts on the same Bible his father used in Michigan.
Question from @FunkyZedo: Why are voters disappointed with Obama - he created 5 million jobs, ended Iraq war, Bin Ladin killed, etc?
Katty answers: Expectations for Obama were high. The economy is still struggling. Unemployment is 7.8%. Not all his fault.
Question from @SmartGuyLA: Do you think there's any appetite to abolish the electoral college, a clearly outdated 18th centurey relic?
Katty answers: No.
Question from @MertensA Which state do you think will surprise people and vote against the candidate that polling suggests is leading?
Katty answers: Hmm...perhaps Florida. Romney is up but the Puerto Rican vote could tip it to Obama.
Richard in London emails: What time do you think we'll see a clear result next Tuesday night? How late will I be staying up?
Katty answers: In 2008 the election was called by 11PM - this time it could be later. It depends on a few tight counties in Ohio.
For more tweets from Katty Kay you can follow her Twitter account: @KattyKayBBC