By the time Goldwater came to Nixon, it was too late. However, there were not necessarily enough Senators ready to remove him after the articles of impeachment left committee. Nixon did a lot of stupid things in dealing with the impeachment. Things like firing the investigating attorneys, fighting release of the tapes, doing nothing after the tapes were released to inoculate himself, not "taking care" of Hunt, the Plumbers, etc.
Nixon could have survived and finished his term had he conducted a Clinton-style offensive rather than circling the wagons. He should have attacked the Watergate Committee members (something to the effect of theyre trying to overturn a legitimate election because theyre mad their hippie bed wetting commmie fellow traveller McGovern lost), destroyed the tapes, fired but paid off those that could have hurt him, etc. He might have survived, but the story could have gotten out eventually and bit him in the rear. Instead of becoming an elder statesman respected by future leaders, he could have just become a joke.
I can feel the pending assaults coming. Please understand, Im writing this as a realpolitik option.