A "diplomatic solution" refers to finding a peaceful and negotiated way to resolve a problem or conflict between countries through diplomacy, discussion, and compromise, rather than resorting to violence or force. Full definition
Rep. Chris Collins (R - 27) welcomed a potential diplomatic solution to the standoff with Syria, but criticized President Obama for allowing Russia to craft it. (nystateofpolitics.com)
What the BBC journalist hadn't noticed was that the Guardian's polls had asked only very limited questions and failed to give respondents the option of saying they would prefer diplomatic solutions. (religion-online.org)