A half a dozen California communities, struggling to recover from the housing downturn, are revisiting an idea to seize mortgages through eminent domain -- a plan rejected five months ago by three other municipalities in the state. The lending industry has been fighting Mortgage Resolution Partners (MRP), a San Francisco firm that has pushed the controversial plan as a way to help borrowers reduce loan balances when the remaining mortgage payments exceed the value of the underlying property. With eminent domain, a government can forcibly acquire property for reuse in a way considered beneficial to the public. MRP is trying to persuade cities to use eminent domain to acquire underwater mortgages from investors and lower the loan principal to match the current property value. The cities would then resell the reduced mortgages to new investors, with MRP collecting a fee. Supporters say the plan would help free residents of restraining debt loads and prevent foreclosures that erode the tax base. Critics counter that the housing rebound is already fixing the problem of underwater loans, that the eminent domain approach does nothing to help the neediest borrowers, and that the program works only if judges assign a price to loans that are below market value.