A grey area in these democracies is the so-called "revolving door" in which politicians are offered highly-paid, often consultancy jobs upon their retirement from politics by the corporations they regulate while in office, in return for enacting legislation favourable to the corporation while they are in office, a conflict of interest. Convictions for this form of bribery are easier to obtain with hard evidence, a specific amount of money linked to a specific action by the recipient of the bribe. Such evidence is frequently obtained using undercover agents, since evidence of a quid pro quo relation can often be difficult to prove. See also influence peddling and political corruption.