and promote their policy agenda. Many political parties and candidates engage in a practice called clientelism, in which they distribute material rewards to people in exchange for political support; in many countries this is illegal, though even where it is illegal it may nevertheless be widespread in practice. Some parties engage directly in vote buying, in which a party gives money to a person in exchange for their vote. Though it may be crucial for a party to spend more than some threshold to win a given election, there are typically diminishing returns for expenses during a campaign. Once a party has crossed a particular spending threshold, additional expenditures might not increase their chance of success. Restrictions Fundraising and expenditures by political parties are typically regulated by governments, with many countries' regulations focusing on who can contribute money to parties, how parties' money can be spent, and how much of it can pass through the hands of a political party. Two main ways in which regulations affect parties are by intervening in their sources of income and by mandating that they maintain some level of transparency about their funding. One common type of restriction on how parties acquire money is to limit who can donate money to political parties; for example, people who are not citizens of a country may not be allowed to make contributions to that country's political parties, in order to prevent foreign interference. It is also common to limit how much money an individual can give to a political party each election. Similarly, many governments cap the total amount of money that can be spent by each party in an election. Transparency regulations may require parties to disclose detailed financial information to the government, and in many countries transparency laws require those disclosures to be available to the public, as a safeguard against potential corruption. Creating, implementing, and amending laws regarding party expenses can be extremely difficult, since governments may be controlled by the very parties that these regulations restrict. Party colours and symbols Nearly all political parties associate themselves with specific colours and symbols, primarily to aid voters in identifying, recognizing, and remembering the party. This branding is particularly important in polities where much of the population may be illiterate, so that someone who cannot read a party's name on a ballot can instead identify that party by colour or logo. Parties of similar ideologies