How Does a Decrease in Miner Participation (Due to Halving) Potentially Affect Network Security?

A significant decrease in miner participation leads to a lower total network hash rate. A lower hash rate means that a malicious actor would require less computational power to control over 50% of the network.

This control is necessary to execute a "51% attack," which could allow them to reverse transactions and double-spend coins. The network's difficulty adjustment mechanism is designed to eventually lower the difficulty, restoring profitability and attracting new miners to maintain security.