It can be tempting to copy someone else's ideas and pass them off as your own. Theresa May seems to have done just that for her speech to Conservative Party Conference today, with a line from American TV drama The West Wing. It looks like she, or one of her speechwriters, is an Aaron Sorkin fan. Compare the (fictional) President Jed Bartlet with the (still real, just about) Prime Minister Theresa May.
Here's Bartlet: "Every time we think we have measured our capacity to meet a challenge, we look up and we're reminded that that capacity may well be limitless".
And here's May, in a line given to the media in advance of her speech: "And it is when tested the most that we reach deep within ourselves and find that our capacity to rise to the challenge before us may well be limitless".
As Theresa May said during her first PMQs: remind you of anyone?
People have said a lot of things about our Prime Minister, but I don't think even her strongest admirers would say she has a limitless capacity to rise to a challenge. Not since the election campaign, anyway.
The problem is that this isn't the only example of plagiarism from the Conservative Party and the Prime Minister this week. Their whole policy agenda now consists of a series of low-quality bootleg versions of better Labour ideas.
Take the big announcements in her speech. A "rebirth" of council house building - we wait for the detail, but it sounds very like a policy from Labour's manifesto. Action on energy prices - I'm old enough to remember when Ed Miliband announced that and got accused by the Tories of living in a "Marxist universe". Stopping further rises in student fees - it's pretty weak compared to Labour's plan to scrap tuition fees, but at least the Tories have finally noticed the problem.
The Tories have realised Jeremy Corbyn is onto something, but they have no idea what to do about it. This time last year the Tories were laughing at him. Now they're copying him.
The problem with plagiarism is that once you spot it, it's hard to respect the person responsible. If the Tories can't come up with ideas of their own, why should anyone listen to them any more? It's Labour that's setting the agenda. Beware of cheap knock-offs.