Nick Broomfield on filming Sarah Palin

I didn’t really know that much about Sarah Palin. I remember being kind of blown away when she got up on that stage with all those kids and gave that rather brilliant speech which seemed to be an enormous breath of a fresh air for the Republican Party. This film was done before the Tucson shootings. I don’t think she’s revealed just how horrible she could really be. To that extent I think I had a fairly open mind.

I was aware of her contempt for education and established politicians but I had enough curiosity to give her the benefit of the doubt. I knew nothing about evangelical religion.

When I first went to Wasilla in Alaska things didn’t really go that well from the beginning. Our entry was supposed to be hush hush but we couldn’t have arrived with more noise if we’d tried. I had been pretty discreet in doing the research - I avoided doing any big phone calls myself. And then when we all landed my producer and main researcher got deported because they didn’t have a journalistic visa.  The homeland security called up all the people we’d been calling. If an elephant had parachuted from a plane into Wasilla they couldn’t have made more noise.

She persistently stabbed the people who were closest to her in the back

Early on I called her parents a couple of times and once we got the mother and she said, ‘You’ll have to go through Todd [Palin].’ Going through Todd is like trying to break into Fort Knox. It’s just not going to happen. He pre-vets everything and just says no. And then I called again and just happened to get the father who was obviously in a jolly mood and he said, ‘Oh come over now.’ So we did a skid turn in the snow and zoomed back there before he could do anything or before there would be an accidental phone call with Todd.

From being extremely positive - we’d almost had to fight our way out of the house after two or three hours – to very guarded the next time we saw him seemed quite incredible. But that’s what happens: a switch goes and you are suddenly the enemy. They became obsessed by that time that we were doing a hit job. I think it’s to do with her evangelical upbringing. They have zero tolerance for people who disagree with them. She carried on with the same kind of extremely vengeful behaviour when she was the governor. For Steve Schmidt, who was campaign manager for Bush and McCain, to comment on how vengeful she was meant that she was really pretty bad. He was used to bodies in the cupboard and he singled her out as someone who persistently stabbed the people who were closest to her in the back.

Watch the trailer to Sarah Palin: You Betcha

Given that we live in a world full of people who are very controlling and unaccountable, you can’t just make films about people where you’re guaranteed a happy outcome. But I did spend three months trying to get the interview so it was frustrating. By that time we were just so unpopular with the family. It was impossible to be a part of this teeny community without speaking to someone they didn’t approve of. But I think that is part of the portrait of who they are and how they thought. I don’t think she is dim. Even though she was incompetent and uninterested in the day-to-day business of government, very bright people who I respect a great deal talk about her as being the best campaigner they’d ever worked with. She enjoyed going into battle, the cut and thrust of the campaign. She wasn’t interested when the campaigning had finished. She’s fantastic in a stadium of 10,000 people. Her problem is when she’s on a one-to-one.

I actually thought we would pull it off and we would get an interview but it was probably naive to think that. Maybe I was hoping at one point to find an open lucid moment where she would open up but she’s never been very open. She has been so battered by the press that she’s just very guarded. Whenever someone is paranoid and extremely defensive, that is their own worst enemy. What she did after Tucson was like committing political suicide: she just could not apologise.

The downside of following a news story is you never know which was it’s going to go. Documentaries on the whole are fairly reflective and I don’t think they necessarily work best as unfolding news stories. It’s fine to involve the audience in a hunt. When you do get those revelations - whether it’s Aileen Wuornos or Heidi Fleiss or even in a bizarre way Eugene Terreblanche - they are moments of gold and they make the rest of the agony worth it, which is why it’s frustrating when you don’t get it. Maybe there isn’t this open, charming, delightful individual to be revealed. You could take Sarah out of Wasilla but you couldn’t take Wasilla out of Sarah.

• Sarah Palin: You Betcha! is on More4 at 10pm on 27 December
• Nick Broomfield's website
• Nick Broomfield was talking to Jasper Rees