Germany has the highest level of public funding for political parties, with the state providing around 50% of their income.

The United States has the lowest level of public funding for political parties, with the state providing less than 1% of their income.

Private donations are the main source of income for political parties in the United States, accounting for over 90% of their income.

Public funding is the main source of income for political parties in the United Kingdom, accounting for over 50% of their income.

Private donations are the main source of income for political parties in Canada, accounting for over 70% of their income.

Public funding is the main source of income for political parties in Australia, accounting for over 50% of their income.

Germany has the most restrictive laws on political party funding, with strict limits on the amount of money that parties can receive from private donors.

The United States has the least restrictive laws on political party funding, with few limits on the amount of money that parties can receive from private donors.

All of the above are main arguments in favor of public funding of political parties.

All of the above are main arguments against public funding of political parties.

All of the above are main challenges facing political party funding in the 21st century.

All of the above are possible reforms to political party funding.

All of the above are possible futures for political party funding.

All of the above factors are important in determining the success of a political party.

All of the above are important challenges facing political parties today.