have hardened support for

[GoodTaste]

Even though Omicron is tough to contain, its increased transmissibility and ability to evade vaccine-derived immunity have hardened support for China’s unwavering strategy among some scientists.

Source: Nature

Is “hardened” an adjective or a past participle? If the former, it appears to mean determined: if the latter, it seems to mean strengthened. I am not very sure.

 

[5jj]

have hardened - present perfect of the verb harden

 

[GoodTaste]

What does it mean?

 

[tedmc]

The support (by the public I presume) for the scientists' strategy has become stronger

 

[5jj]

It's China's strategy. The support is from some scientists.