@Setanta,
It is indeed highly improbable that the Senate would convict Trump if for no other reason than neither party wants to be the only one with a President who has been kicked out of office, and barring Trump actually being seen on TV shooting someone on 5th Avenue, all Republicans will rally around him to prevent it.
Right now the score is roughly tied: Two impeachments for the Dems and one resignation for the GOP.
However, as much as the Dems would do well to heed your advice, considering how far left their party is being driven by its base, if they should take back both the Senate and the House, I can very easily imagine them tilting at that particular windmill.
If they win back the House (very possible and some think probable) I believe it's a foregone conclusion that they will impeach Trump. First of all their base will expect and
demand it, and secondly they are looking for payback after Clinton.
Conventional wisdom is that the House is where the tempestuous children hang out causing tumult; while the Senate is where the adults in Congress tend to the nation's longer range interests. The Kavanaugh hearings, at least in terms of the Democratic Senators, certainly belie this notion. I think however that the distinction is driven more by the length of a Representative's term and the size and nature of their voting districts than any material difference in temperments. Afterall, a great many Senators began their careers in the House.
With districts drawn by gerrymandering to favor one party or the other, Representatives are even more motivated by the partisan desires of the respective bases of their parties. It's hardly a stunning insight to recognize that Senators must attract a broader pool of voters. At the same time two years is a very short time for a politician to make a name for him or herself, and the re-election campaign begins the next day after an election victory. There is every reason to believe that The Resistance will be going strong for the next two years and the Dems Reps up for re-election in 2020 cannot afford to be seen as missing the tide if they hope to come back for another 2 years. If given the opportunity to impeach Trump they will have to take it and they will likely take it quite happily.
Senators with their 6 year terms can more easily afford a
wait-and-see approach, however 2020 brings a presidential election too and right now there are at least 5 Dem Senators (including Sanders) who are already running for their party's nomination. If a Democrat House impeaches Trump in 2019 these five will want to be seen as the champion of
The Resistance. We have already seen this with the hyper-aggressive antics of Harris and Booker on the Senate Judicial Committee and Gillibrand's attempt to attach herself to the anti-Kavanaugh attack squad. Senators Coons, Hirono and Bluementhal have been vying with Harris & Booker to be seen as the Lead Assassin and may have up their sleeves a notion of running themselves. Should Trump be impeached in 2019 any Democrat Senator with an eye on 2020 will be motivated to lead an effort for conviction in the Senate. Should the effort pick up any momentum it's hard to imagine a Democrate Senator willing to stand up to the
Resistance Mob's bloodlust ( Manchin, Donnelly, McCaskill and Heitkamp will all either be gone or in place with 5 years of breathing room in 2019)
Again, you are almost certainly correct that barring a totally unforseen Red Tidal Wave in November, any attempt to convict Trump in the Senate will fail, but the short term motivation and possible reward for enough Dem Senators might drive an effort that is doomed to failure in its ostensible goal, but could nevertheless provide, even in defeat, essential
Resistance bonafides for 2020 hopefuls.
Corey Booker might have another chance for a "I am Spartacus" moment.