In "The Poet," Emerson writes: 

For all men live by truth, and stand in need of expression. In love, in art, in avarice, in politics, in labor, in games, we study to utter our painful secret. The man is only half himself, the other half is his expression. 

Since the poet is he/she who can best express the virtues and beauty of our nature, the poet is our best "representative." In the context of individuals and government, the indication is that a politician who lacks this poetic skill (being sensitive to the impressions of nature, in form and character) will be an inadequate representative of humanity. Emerson actually uses the word "representative" to describe the poet. 

The breadth of the problem is great, for the poet is representative. He stands among partial men for the complete man, and apprises us not of his wealth, but of the common-wealth. 

Just as the poet is in tune to, and thrilled by, the common, daily occurrences in nature, the poet is therefore in tune to the daily experiences of the common man. A potential solution to this problem (that poets understand more than governments) is to elect poets instead of politicians; or it is for every common person to pursue this poetic skill of expression. Even if a person can't become a published poet or a public/political speaker, he/she can become more attuned to nature and what's going on the in the world by paying attention to things in nature and culture. Since half of man is expression, he (/she) should pursue poetic expression not just for self-completion but to understand the world more fully. 

Another interpretation/solution from this context about "expression" is that people should vote for "representatives" who truly represent and express significant truths: those who understand the connection between words, symbols, and nature. It is a lesson not just for poets and politicians but for all people (which returns to Emerson's theme of Self-Reliance).