These are the packages that would be merged, in order:

Calculating dependencies... done!
[ebuild   R    ] sys-auth/polkit-kde-agent-0.99.0  USE="(-aqua) -debug" LINGUAS="ru -ca -ca@valencia -cs -da -de -en_GB -eo -es -et -fi -fr -ga -gl -hr -hu -is -it -ja -km -lt -mai -ms -nb -nds -nl -pa -pt -pt_BR -ro -sk -sr -sr@ijekavian -sr@ijekavianlatin -sr@latin -sv -th -tr -uk -zh_TW" 0 kB
[ebuild   R    ] kde-misc/polkit-kde-kcmodules-0.98_pre20101127  USE="(-aqua) -debug" 0 kB
[ebuild  N     ] sys-auth/polkit-kde-0.95.1-r1  USE="(-aqua) -debug" LINGUAS="-da -en_GB -et -gl -lt -nl -pt -pt_BR -sk -sv -uk -zh_TW" 21 kB
[blocks B      ] sys-auth/polkit-kde-agent ("sys-auth/polkit-kde-agent" is blocking sys-auth/polkit-kde-0.95.1-r1)
[blocks B      ] >=sys-auth/polkit-qt-0.99 (">=sys-auth/polkit-qt-0.99" is blocking sys-auth/polkit-kde-0.95.1-r1)
[blocks B      ] sys-auth/polkit-kde ("sys-auth/polkit-kde" is blocking sys-auth/polkit-kde-agent-0.99.0)

Total: 3 packages (1 new, 2 reinstalls), Size of downloads: 21 kB
Conflict: 3 blocks (3 unsatisfied)

 * Error: The above package list contains packages which cannot be
 * installed at the same time on the same system.

  (sys-auth/polkit-kde-0.95.1-r1::gentoo, ebuild scheduled for merge) pulled in by
    polkit-kde

  (sys-auth/polkit-qt-0.103.0::gentoo, installed) pulled in by
    >=sys-auth/polkit-qt-0.98_pre required by (kde-misc/polkit-kde-kcmodules-0.98_pre20101127::gentoo, ebuild scheduled for merge)
    >=sys-auth/polkit-qt-0.98_pre required by (sys-auth/polkit-kde-agent-0.99.0::gentoo, ebuild scheduled for merge)
    >=sys-auth/polkit-qt-0.95.1 required by (sys-auth/polkit-kde-0.95.1-r1::gentoo, ebuild scheduled for merge)

  (sys-auth/polkit-kde-agent-0.99.0::gentoo, ebuild scheduled for merge) pulled in by
    >=sys-auth/polkit-kde-agent-0.98_pre required by (kde-misc/polkit-kde-kcmodules-0.98_pre20101127::gentoo, ebuild scheduled for merge)
    polkit-kde-agent


For more information about Blocked Packages, please refer to the following
section of the Gentoo Linux x86 Handbook (architecture is irrelevant):

http://www.gentoo.org/doc/en/handbook/handbook-x86.xml?full=1#blocked