The phrase "able to insist" is correct and usable in written English.
You can use it when describing someone's capability or authority to assert or demand something firmly.
Example: "She was able to insist on her terms during the negotiation."
Alternatives: "capable of insisting" or "in a position to insist".
"So Britain will be able to insist, for future countries joining, we'll be able to insist on a tougher, more robust regime".
So Britain will be able to insist for future countries joining, we'll be able to insist on a tougher, more robust regime".
Those wanting MRRT gone won't be able to insist on today's amendments".
Won't Tea Party groups be able to insist that their opposition to Boehner's bill was entirely vindicated?
They are able to insist that their daughters go to school, because they can pay for it.
But when they were powerful, unions were able to insist that government policy respond to the views of the poor and the middle class.
During our phone conversation and several e-mail exchanges, he was unstinting in his use of the words "right" and "wrong," and nearly all of his voluminous writings, talks, and interviews (and e-mails to journalists, so far as I am able to determine) insist that his listeners or readers behave differently, and better.
Thus, recognizing that parents may not be able or willing to insist upon vaccination of vaccine-hesitant adolescents, vaccination efforts may need to incorporate methods that incentivize adolescents directly.
I don't know whether we would have been able to agree and to insist on the implementation of our agreements with a different person at the helm of American government.
To call the Aurora killer evil is to insist that he was able to choose between inflicting tremendous harm or not doing so, and chose harm.
Thus, every person wearing a polo or a romper is going to insist that they be able to look at your camera to size up your work.
