The most important safeguard of liberty is a bold and impartial judiciary (option-1). A bold judiciary refers to a judicial system that is courageous and independent, capable of making decisions without fear or favor. An impartial judiciary ensures that all individuals are treated fairly and equally under the law, without any bias or prejudice.

The judiciary serves as a check on the powers of the executive and legislative branches, ensuring that they do not infringe upon the rights and liberties of individuals. It interprets and upholds the constitution, protecting the fundamental rights of citizens.

While options 2, 3, and 4 can also contribute to safeguarding liberty to some extent, they are not as crucial as a bold and impartial judiciary. A well-knit party system (option-2) promotes political stability and competition, but it alone cannot guarantee the protection of individual liberties. Decentralisation of power (option-3) can prevent the abuse of power but is not sufficient to safeguard liberty. Declaration of rights (option-4) can express the values and principles of a society, but without an effective judiciary to enforce them, they may remain mere words.