the whole nation; everyone in the country
新法は全国民に関わる問題だ。
The new law is an issue that concerns the entire nation.
新しい政策は全国民に負担となるだろう。
The new policy will likely become a burden on the entire nation.
その決定は全国民の生活に大きな影響を及ぼした。
That decision had a significant impact on the lives of the entire nation.