"bulwark for" is correct and usable in written English.
You can use it when referring to someone or something providing protection or support. For example, "She had been a bulwark for her family in times of need."
We cannot even rely on incompetence as a bulwark for our freedoms.
The United Nations has lately (at America's urging) started up a "Democracy Fund" as a bulwark for fragile democracies.
While consumer spending has continued to grow, providing the main bulwark for the ailing economy, it has definitely softened.
He said: "Strict safeguards to protect parliamentary communications are an important bulwark for the protection of the public interest".
Cuccia founded the bank in 1946 as a bulwark for industrialists against the rising tide of post-war communism in Italy.
But there are now a plethora of cover-ups — even if they are more about a return to tailoring than a bulwark for a cold snap.
He then made a quick right turn, however, linking progressive principles to the free market and voluntary networks as if they are sufficient bulwarks for a global economy in the 21st century.
The trade unions are a bulwark of support for the opposition Movement for Democratic Change and produced its current leader, Mr. Tsvangirai.
In this affluent northern city, usually a bulwark of support for the king, some demonstrators spoke openly of demands for democracy.
The Israelis are quite nervous that their peace treaty with Egypt, a bulwark of stability for so long, could erode.
"The current law on assisted suicide is a bulwark of protection for vulnerable people against vested interest.
