"increasingly undermined" is a correct and usable phrase in written English.
It can be used as a verb phrase to describe a situation where something is becoming weaker or less effective over time. Example: The company's profits were increasingly undermined by rising costs and a decrease in consumer demand.
Their power base in Iran's parliament has been increasingly undermined by the president's energetic use of his executive authority.
His authority has been increasingly undermined because Mr. Putin has pointedly refused to exclude seeking a return to the presidency himself.
Yet as a whole, human rights experts say the European Union is allowing its values to be increasingly undermined by the rise of China.
Key concepts of rights and choice are increasingly undermined by stricter rationing, tightened eligibility criteria and top-up fees, familiar features also of England's system.
However, those who continue to deny the connection between extreme rainfall in the UK and climate change are looking increasingly undermined by the growing evidence, said Professor Myles Allen of Oxford University.
But another front has now opened: American soft power — its ability to attract and persuade — is increasingly undermined by the government's inability to take strong action on climate change, something that local opposition to clean energy development only makes worse.
But the reality of rising access to cheap shale gas will in any event increasingly undermine the profitability of coal.
As Syria's crisis increasingly undermines the stability of its fragile neighbors, Assad's leverage in the international community, via the Russians, who have been his stalking horse from the beginning, becomes greater.
Two developments are increasingly undermining this argument.
To sum up, above all, fictitious self-employment ("Scheinselbständigkeit"), minor working contracts, temporary agency work and non-permanent part-time work are increasingly undermining labour law and social law regulations.
It followed an Ofsted inspection that concluded relationships between governors, school staff and the local authority had deteriorated markedly; actions by the governing body were increasingly undermining senior leaders; and governors were becoming too involved in operational matters.
