A stable aqueous dispersion of multiphase amphoteric polymer particles comprising: a) a crosslinked polymer phase comprising, based on the weight of the crosslinked polymer phase: i) from 1 to 10 weight percent structural units of a phosphorus acid monomer or a salt thereof; ii) from 0.5 to 5 weight percent structural units of a carboxylic acid monomer or a sulfur acid monomer or a salt thereof or a combination thereof; iii) from 1 to 10 weight percent amine groups or salts thereof or quaternary ammonium salts; iv) 0.2 to 10 weight percent structural units of a multiethylenically unsaturated monomer; and v) from 80 to 97 weight percent structural units of an ethylenically unsaturated nonionic monomer; and b) a second polymeric phase comprising: i) from 0.1 to 4 weight percent structural units of a carboxylic acid monomer or a sulfur acid monomer or a salt thereof or combination thereof, based on the weight of the first polymeric phase; and ii) from 80 to 99.9 weight percent structural units of an ethylenically unsaturated nonionic monomer; wherein the second polymer phase has a T g in the range of from -20 °C to 75 °C; wherein the crosslinked polymer phase protuberates from the second polymer phase; wherein the weight:weight ratio of the crosslinked polymer phase to the second polymer phase is in the range of from 1:4 to 1:35; wherein the average particle size of the crosslinked polymer by dynamic light scattering is in the range of 40 nm to 90 nm; and wherein the average particle size of the multistage particles by dynamic light scattering is in the range of 110 nm to 190 nm; with the proviso that the multiphase amphoteric polymer particles comprise from 0.01 to 4 weight percent structural units of the phosphorus acid monomer or a salt thereof and from 0.01 to 4 weight percent of the amine groups or salts thereof or the quaternary ammonium salt groups. a) a crosslinked polymer phase comprising, based on the weight of the crosslinked polymer phase: i) from 1 to 10 weight percent structural units of a phosphorus acid monomer or a salt thereof; ii) from 0.5 to 5 weight percent structural units of a carboxylic acid monomer or a sulfur acid monomer or a salt thereof or a combination thereof; iii) from 1 to 10 weight percent amine groups or salts thereof or quaternary ammonium salts; iv) 0.2 to 10 weight percent structural units of a multiethylenically unsaturated monomer; and v) from 80 to 97 weight percent structural units of an ethylenically unsaturated nonionic monomer; and i) from 1 to 10 weight percent structural units of a phosphorus acid monomer or a salt thereof; ii) from 0.5 to 5 weight percent structural units of a carboxylic acid monomer or a sulfur acid monomer or a salt thereof or a combination thereof; iii) from 1 to 10 weight percent amine groups or salts thereof or quaternary ammonium salts; iv) 0.2 to 10 weight percent structural units of a multiethylenically unsaturated monomer; and v) from 80 to 97 weight percent structural units of an ethylenically unsaturated nonionic monomer; and b) a second polymeric phase comprising: i) from 0.1 to 4 weight percent structural units of a carboxylic acid monomer or a sulfur acid monomer or a salt thereof or combination thereof, based on the weight of the first polymeric phase; and ii) from 80 to 99.9 weight percent structural units of an ethylenically unsaturated nonionic monomer; i) from 0.1 to 4 weight percent structural units of a carboxylic acid monomer or a sulfur acid monomer or a salt thereof or combination thereof, based on the weight of the first polymeric phase; and ii) from 80 to 99.9 weight percent structural units of an ethylenically unsaturated nonionic monomer;