"It is for you to define the concrete implementation arrangements with a much greater leeway compared to today."
MEPs are voting on three separate legal proposals to reform the post-2020 CAP. The most controversial is a new law requiring governments to submit annual "strategic plans" setting out how they intend to spend EU subsidies - with penalties for those who fail to meet EU objectives.
Most EU countries fear that the extra paperwork and reporting required under the strategic plans (and accompanying progress reports) will overcomplicate an already labyrinthine system.
"The CAP, under the guise of simplification, is being made even more complicated, bureaucratically," Mr Carthy told the Farming Independent. "Farmers find themselves in a tug of war between the European Commission and national governments."
The other two proposals include a rejigged law on emergency aid and market intervention (known as the 'common markets organisation') and a 'horizontal' law on how CAP money is paid out (including advances, sanctions and exemptions).
They are also squabbling over what defines a 'genuine farmer' and what type of land will qualify for future subsidies, as well as a controversial €60,000-100,000 limit on direct payments.
The cap is seen as the only way to ensure a fairer redistribution of CAP money from bigger to smaller farmers, and between EU countries (known as internal and external convergence, in EU jargon).
Ireland already applies a voluntary upper limit of €150,000 on CAP payments, and Government figures show that 99pc of eligible Irish farmers received basic payment below €60,000 in 2018.
A group of largely eastern European countries - led by the Czechs - is also lobbying the Commission to double the amount of money set aside for specific sectors and products ('voluntary coupled support').
However, the discussions on the future CAP are inextricably linked to discussions on the EU's 2021-27 budget, which EU leaders want to wind up by this autumn.
Mr Carthy says the Irish Government "has played their hand very badly" in the budget talks - particularly with the threat of a 'no-deal' Brexit looming.
"I don't think you can [agree] on the new CAP process without having the budget locked down," he said.
"And I don't see any way the Irish people will support a European budget where they're getting less back."
Along with EU farmers' organisations, Mr Carthy is pressing for an emergency Brexit fund to help specific regions and sectors dealing with Brexit.
"The Irish Government refuses to place that demand on the European Commission - they have adopted a wait and see approach," Mr Carthy said.
"They are talking about existing instruments but Brexit is beyond anything we've seen before.
"In a no-deal scenario the Irish exchequer would not be in a position to provide, on its own, this type of assistance."