Under existing rules the bloc needs the approval of 40 parliaments across Europe before it can sign off any agreements.
This weakness saw the Belgian region of Wallonia almost blow a hard-fought EU trade agreement with Canada out of the water last year when it decided to dig its heels in on tariffs.
So to avoid similar future fiascos Mr Juncker has proposed fast-tracking the ratification of trade deals to eliminate the potential for local and national governments to stand in the way.
The commission chief wants to build on the momentum of a landmark deal struck with Japan in July with brisk progress on agreements with Australia and New Zealand.
Diplomats say these two deals will be the first to use a new framework that would allow ratification without the danger of a veto from any of the sometimes rebellious national and regional parliaments.
The new model involves splitting deals into two parts.
Most chapters in trade accords fall under the exclusive competence of the EU, meaning those sections can be ratified by the European Parliament and EU governments as represented at the Council.
The only reason national parliaments become involved is that some sections of the agreements related to investment — most contentiously the rules for big investors suing governments — do require approval back in the member countries.
The Commission’s plan is to carve out the parts of the deals related to investment so that the lion’s share of the trade pacts can be approved in Brussels.
A Commission official confirmed the plans to start talks with Australia and New Zealand under the fast-track approach but cautioned it was not yet certain whether the president would trumpet that plan in his State of the European Union Address on September 13.
He said: “Maybe Mr Juncker will just allude to it. But this is coming.”