"We don't do policy by polls," Blinken said when asked about recent polls showing waning public support for the conflict in Ukraine.
"We do policy based on the interests of the United States and the interest of the United States is clearly in supporting and helping Ukraine defend itself against this aggression from Russia."
Blinken said he believes that Americans "across the board" care about the situation in Ukraine and the world can become much more challenging for the United States if Washington decides not to support Kiev in its conflict with Russia.
On Monday, a new poll by the Chicago Council on Global Affairs found that only 40% of Americans believe the United States should maintain its current level of support for Ukraine indefinitely.
In addition, the poll found that Americans remain divided on whether the United States should support Ukraine "as long as it takes" - 48%, supporting that view from the 58% reported in July.
The United States to date has provided Ukraine with at least $20 billion in military assistance since the beginning of the Biden administration and has earmarked significantly more for military, economic and other aid.