Supporters of campaign finance reform demonstrate outside the U.S. Capitol in 2014. (Win McNamee/Getty Images)

Each week, In Theory takes on a big idea in the news and explores it from a range of perspectives. This week, we’re talking about corruption. Need a primer? Catch up here.

Jacob Rowbottom is an associate professor of law at Oxford University and a fellow of University College, Oxford. He is the author of “Democracy Distorted and of numerous articles on campaign finance and free speech.

Corruption is a morally charged word. When we say someone is corrupt, we don’t just mean that a person broke a rule or failed to meet an expectation. The word implies something is rotten at its core, that something fundamental has been betrayed. The power of the word can get attention, mobilize public opinion and express disapproval in the strongest terms.

Given the power of the term, it is unsurprising that its meaning is hotly debated in the field of politics, not least when it comes to the impact of money on policymaking. The narrow view of corruption taken in U.S. courts — along with an attitude of distrust of government — has shaped the U.S. campaign finance system into something vastly different from those in other countries, such as Britain.

In the United States, Chief Justice John Roberts has defined corruption primarily in terms of quid pro quo. In his view, “mere influence and access” secured by political money is not corruption. By contrast, campaign finance reformers take a view of corruption that includes and extends beyond backroom deals. In their view, money can corrupt the political system — for example, by forcing politicians to give disproportionate attention to wealthy individuals and organizations.

Underlying this disagreement are divergent views about how the democratic system should function. The majority in the Supreme Court sees attention to donors as an element of the responsiveness expected of politicians. Reformers, however, expect politicians to distribute their attention to those who deserve it, rather than to those with the ability to spend large sums.

The use of “corruption” as a blanket term can mask these underlying and important tensions. However, the language of corruption is an important rhetorical tool to show how bad things have become and how money strikes at the core of democracy.

While the Supreme Court sees only limited scope for money to corrupt politics, it is more than willing to suspect that officeholders will abuse their powers to limit the speech of opponents. Justice Anthony Kennedy famously said that the First Amendment is “premised on mistrust of governmental power.”

By contrast, Lord Bingham, sitting as a judge in the United Kingdom’s highest court, said in 2008 that British courts should be reluctant to interfere with the judgment of the legislature on political finance matters because it “is reasonable to expect that our democratically-elected politicians will be peculiarly sensitive to the measures necessary to safeguard the integrity of our democracy. It cannot be supposed that others, including judges, will be more so.”

Where the United States sees a risk of politicians abusing power, Britain trusts politicians as experts on matters relating to the political process. Although this assumption of trust may be complacent, the other extreme of mistrust is also problematic. Our fear of abuse of government power should not require constitutional constraints that disable government from building a fairer political system, one that addresses the disproportionate influence of private power.

British campaign finance laws are very different from those in the United States. In some areas, the controls are less strict: There is no limit on the size of a political contribution; companies can contribute out of general treasuries; and only relatively large donations need to be disclosed. However, in Britain there are limits on the amounts that political parties and candidates can spend in a single election. Spending limits are also applied to independent election spending. More broadly, all political advertising on television and radio is banned, and broadcasters are required to show “due impartiality” on matters of political controversy. The courts have so far upheld these laws, reflecting the mistrust of concentrations of private power that is a feature of British political culture.

The cost of an election is much lower in Britain. than in the United States, partly due to differences in the political system, but also partly due to the campaign finance laws. Most obviously, the absence of paid television advertising in Britain means that political parties do not need to secure vast reserves of money to saturate the airwaves. Although enactment of the laws is not perfect, they have helped control the cost of elections.

Britain’s experience also shows that there is a limit to what can be achieved by regulating election spending. Britain has its fair share of political finance scandals, in some cases alleging corruption. More broadly, money can secure political influence when used to build the infrastructure in which election messages are interpreted. This includes the private financing of think tanks and, most visibly in Britain, the ownership of the media. While the amount people can spend in an election campaign is limited, the campaign finance laws exempt the media. That means Rupert Murdoch and other media moguls can use their newspapers for electoral advocacy without any limit.

In the United States, however, elections are the most pressing and problematic point of entry for money in the democratic process. When people denounce the existing system as corrupt, the word may mask the underlying issues, but it makes a powerful and pressing moral case for change in the political system — whether through legal controls or the subsidizing of campaigns.

Explore these other perspectives:

Trevor Burrus: When it comes to politics, corruption is subtler than you think

Stephen K. Medvic: The U.S. political system is flawed but not corrupt

Zephyr Teachout: How the Supreme Court gets corruption totally wrong

Daniel Treisman: Does more wealth mean less political corruption?

Nancy Gertner: The corruption continuum — When giving gifts bleeds to bribery